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BOOK    55  1.2  1.D19   c.  1 

DANA    #    CHARACTERISTICS    OF 

VOLCANOES 


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CHARACTERISTICS  ,., 

OF  ,'T)'^ 

VOLCANOES, 


WITH 


CONTRIBUTIONS   OF    FACTS   AND   PRINCIPLES 


FROM 


THE    HAWAIIAN    ISLANDS, 


INCLUDING   A    HISTORICAL   REVIEW   OF   HAWAIIAN   VOLCANIC   ACTION   FOR  THE   PAST 
SIXTY-SEVEN    YEARS,   A  DISCUSSION    OF  THE    RELATIONS   OK   VOLCANIC    ISLANDS 
TO     DEEP-SEA     TOPOGRAPHY,    AND    A    CHAPTER    ON    VOLCANIC- 
ISLAND    DENUDATION. 


By   JAMES    D.    DANA. 


ILLUSTRATED    BY 

MAPS   OF  THE    ISLANDS;  A   BATHYMETRIC    MAP   OF  THE   ATLANTIC   AND    PACIFIC 

OCEANS;    AND   VIEWS   OF   CONES,   CRATERS,   A    LAVA-CASCADE, 

A   LAVA-FOUNTAIN,   ETC. 


NEW    YORK: 

DODD,     MEAD,    AND     COMPANY. 

1891. 


344 


Copyright,  1890, 
By  Dodd,  Mead,  and  Company. 


All  rights  reserved. 


SIniijcrsitg  Press: 
John  Wilson  and  Son,  Cambridge. 


PREFACE. 


np'HE  personal  observations  of  the  author  on  which  this 
book  is  based  commenced  with  the  ascent  of  Vesuvius 
in  1834,  and,  the  next  month,  a  sight  of  Stromboli  and  a 
tramp  after  minerals  on  the  solfataric  island  of  Milo.  They 
were  continued  in  1838  by  short  excursions  on  Madeira  and 
one  of  the  Cape  Verds ;  in  1839,  by  studies  of  the  extinct 
volcanic  regions  of  Xahiti,  Tutuila  and  Upolu,  and  the 
basaltic  outflows  and  overflows  of  Illawarra  and  other  parts 
of  New  South  Wales.  They  were  further  extended  in  1840 
by  observations  in  the  Feejees,  and  by  explorations  of  the 
active  and  extinct  volcanoes  of  the  Hawaiian  Islands ;  in 
1841,  by  observations  on  a  crater  in  the  coast  region  of 
Oregon,  instructive  though  distant  views  of  some  of  the  lofty 
cones  of  the  Cascade  Range,  and  a  brief  survey  of  an  extinct 
volcano  on  the  Sacramento  (now  called  Marysville  Butte) 
during  an  overland  trip  from  Vancouver  to  San  Francisco ; 
and,  finally,  in  1860  by  a  second  visit  to  Vesuvius,  and  in 
1887  a  second  to  the  Hawaiian  Islands. 

The  purpose  of  the  work  is  the  illustration  of  volcanic 
action  and  principles  by  special  reference  to  the  facts  sup- 
plied by  the  great,  open,  free-working  craters  of  Hawaii,  and 
by  comparing  and  contrasting  these  with  the  corresponding 
features  and  phenomena  of  Vesuvius.  It  commences  with 
an  elementary  treatise  on  volcanoes  and  volcanic  action,  that 


iv  PREFACE. 

the  book  may  be  a  convenient  manual  for  the  geological 
student  and  also  for  the  tourist.  After  these  general  ex- 
planations, the  workings  of  the  fires  in  the  two  active 
craters  of  Hawaii  are  successively  set  forth  by  means  of 
descriptions  and  various  illustrations ;  and  a  knowledge  is 
thus  presented  of  the  steps  in  the  progressing  activity,  the 
dependence  of  these  steps  on  one  another,  and  their  relation 
to  the  final  catastrophe.  After  such  a  study  it  becomes  easy 
to  apprehend  the  deductions  which  follow  with  regard  to  the 
methods  and  principles  of  volcanic  action. 

The  work  contains,  in  Part  Third,  an  account  of  the  topog- 
raphy of  the  Pacific  basin,  with  a  map  of  deep-sea  Pacific 
and  Atlantic  soundings,  and  a  discussion  of  the  influence 
upon  the  depth  of  the  oceans  of  volcanic  action.  Further, 
Part  Fourth  treats  of  denudation,  or  valley-making,  on  vol- 
canic islands.  The  subject  is  illustrated  by  a  map  of  the 
island  of  Tahiti,  an  admirable  example  of  water-sculpture, 
and  by  supplementary  facts  from  New  South  Wales  cited 
from  the  author's  ''  Geological  Report  of  the  Wilkes  United 
States  Exploring  Expedition."  Of  this  report  only  one  hun- 
dred copies  were  ordered  for  the  Government ;  and  these, 
with  an  additional  hundred  printed  at  the  time  (fifty-one 
years  ago)  at  the  author's  expense  that  it  might  escape  ob- 
livion, are  all  that  were  ever  issued  ;  hence  some  freedom 
in  copying  its  nearly  inaccessible  pages  has  been  thought 
allowable. 

The  pages  of  this  volume  contain  many  reasons  why 
the  two  active  craters  of  Hawaii  should  share  equally 
with  Vesuvius  and  Etna  in  the  attention  of  investigators. 
Hardly  three  weeks  distant  from  Europe  and  not  two 
from  New  York,  with  much  to  be  seen  on  the  way  and 
tropical  islands  growing  corals  and  tree-ferns  at  the  end, 
the    route    should    be    a    common    one    with    tourists.     The 


PKEFACE.  V 

magnitude  and  easy  access  of  the  great  craters;  their  prox- 
imity, while  nearly  ten  thousand  feet  apart  in  altitude ; 
their  strange  unlikeness  in  ordinary  action,  although  alike 
in  features  and  lavas  ;  their  unsympathizing  independence  ; 
their  usually  quiet  way  of  sending  forth  lava-streams  twenty 
and  thirty  miles  long,  —  make  them  a  peculiarly  instructive 
field  for  the  student  of  volcanic  science,  as  well  as  an  attrac- 
tive one  for  the  lover  of  the  marvellous.  Even  the  lavas, 
although  nothing;  but  basalt,  have  afforded  much  that  is 
new  to  science,  as  is  shown  in  the  chapter  by  my  son, 
Prof.  Edward  S.  Dana. 

Reviewing  the  developments  thus  far  made,  we  find  that 
the  region  has  already  contributed  many  new  ideas  to  the 
vulcanologist.  Science  has  learned  of  volcanic  activity  un- 
restricted by  altitude  up  to  fourteen  thousand  feet ;  of  the 
possibility  of  two  first-class  craters  working  simultaneously 
within  the  area  of  one  mountain-dome,  and  having  the  loftier 
the  more  frequent  and  the  more  copious  in  its  outflows,  and 
neither  of  them  ordinarily  responsive  to  the  other  even  when 
in  eruption  ;  and  of  the  outflow  of  the  heaviest  of  chrysolitic 
lavas  at  various  altitudes  to  the  very  summit. 

Science  has  learned  from  Hawaii  more  than  it  knew  of 
the  mobility  of  liquid  basalt ;  of  the  consequent  range  in 
flow-angle  of  basalt-lavas,  from  the  lower  limit  near  hori- 
zontality  to  the  verticality  of  a  waterfall,  and  therefore  of 
lava-cones  of  the  lowest  angle,  and  driblet-cones  of  all 
angles  ;  of  lava-lakes  tossing  up  jets  over  their  fiery  sur- 
face like  the  jets  of  ebullition,  and  in  other  cases  playing 
grandly  in  fountains  hundreds  of  yards  in  height ;  and,  con- 
sequently, of  the  absence  from  the  craters  of  large  cinder- 
ejections. 

It  has  further  learned  of  a  degree  of  system  in  the 
•changes  within  a  crater  from  one  epoch  of  eruption   to   a 


VI  PEEFACE. 

state  of  readiness  for  another;  of  a  subsidence,  after  an 
eruptive  discharge  of  lava,  that  has  carried  down,  hundreds 
of  feet,  a  large  part  of  a  crater's  floor  without  a  loss  of 
level  in  its  surface ;  and,  following  this,  of  a  slow  rising 
of  the  subsided  floor,  chiefly  through  the  ascensive  or  up- 
thrust  action  of  the  lavas  of  the  lava-column,  and  the  lift- 
ing force  taking  advantage  of  the  fault-planes  that  were 
made  at  the  subsidence ;  and  also  of  debris-ridges  and  of 
debris-cones,  one  to  two  hundred  feet  in  elevation,  made, 
by  the  lift,  out  of  the  talus  of  the  pit-walls. 

It  has  learned  that  pit-shaped  craters  are  characteristic 
of  true  basalt-volcanoes,  and  a  result  of  the  free  mobility 
of  the  lavas,  whether  the  action  in  the  lava-lakes  within 
be  fountain-like  or  boiling-like;  that  floating  islands  of  solid 
lava  may  exist  in  the  lakes ;  that  a  regular  oscillation  be- 
tween fusion  and  cooling  takes  place  at  times  in  the  thin 
crust  of  lava-lakes ;  that  the  solid  lava  of  the  margin  of 
a  lake  may  be  re-fused,  and  also  even  the  mass  of  a  float- 
ing island,  and  the  blocks  of  a  debris-cone  until  the  cone 
has  wholly  disappeared. 

It  has  discovered  that  solfataric  action,  or  that  of  the 
hot  vapors  in  lava-caverns,  may  include  the  recrystalliz- 
ing  of  basalt,  therein  making  it  into  long,  stony  pipe-stem 
stalactites  and  stalagmites,  having  cavities  lined  with  trans- 
parent crystals  of  augite  and  labradorite,  besides  octahe- 
drons of  magnetite. 

It  has  obtained  evidence,  also,  that  the  greatest  of  erup- 
tions may  occur  without  the  violence  or  the  noise  of  an 
earthquake,  and  without  an  increase  of  activity  in  the 
crater;  that  in  place  of  an  increase  there  may  be  a  sud- 
den extinction  of  the  fires,  all  light  and  heat  and  vapors 
disappearing  as  soon  as  the  discharge  begins;  of  the 
greater    frequency    of    eruptions    during    the    wetter    season 


PREFACE.  Vll 

of  the  year ;  of  the  agency  of  fresh  water  from  the  rains 
(and  snows)  in  the  supplying  of  steam-power  for  volcanic 
action ;  of  the  full  sufficiency  of  water  from  this  source 
without  help  from  the  ocean,  —  fresh  water  being  as  good 
as  salt  for  all  volcano  purposes ;  and  further,  of  a  great 
augmentation  of  the  activity  so  produced  with  the  increase 
in  altitude  of  the  working  crater. 

These  are  facts  from  Hawaii  —  and  not  all  that  might 
be  cited  —  that  have  not  yet  been  made  out  from  the  in- 
vestigation of  other  volcanoes,  not  even  the  best  known, 
Vesuvius  and   Etna. 

But  much  remains  to  be  learned  from  the  further  study 
of  the  Hawaiian  volcanoes.  Some  of  the  points  requiring 
elucidation  are  the  following :  the  work  in  the  summit- 
crater  between  its  eruptions ;  the  rate  of  flow  of  lava- 
streams  and  the  extent  of  the  tunnel-making  in  the  flow ; 
the  maximum  thickness  of  streams ;  the  existence  or  not  of 
fissures  underneath  a  stream  supplying  lava;  the  tempera- 
ture of  the  liquid  lava ;  the  constitution  of  the  lava  at  the 
high  temperatures  existing  beneath  the  surface ;  the  depth 
at  which  vesiculation  begins ;  the  kinds  of  vapors  or  gases 
escaping  from  the  vents  or  lakes ;  the  solfataric  action 
about  the  craters ;  the  source  of  the  flames  observed  with- 
in the  area  of  a  lava-lake ;  the  differences  between  the 
lavas  of  the  five  Hawaiian  volcanoes,  —  Kilauea,  Loa,  Kea, 
Hualalai,  and  Kohala ;  the  difference  in  kind  or  texture  of 
rock  between  the  exterior  of  a  mountain  and  its  deep- 
seated  interior  or  centre,  —  for  the  elucidation  of  which 
subject  Kohala's  northern  gorges  may  possibly  afford  mate- 
rial ;  the  difference  between  Loa,  Kea,  and  Haleakala  in 
the  existence  below  of  hollow  chambers  resulting  from 
lava-discharges,  —  a  problem  which  Mr.  E.  D.  Preston  has 
begun    to    solve    by    pendulum    observations,    and    there    is 


Vlll  PREFACE. 

reason  to  hope  may  continue  to  investigate  to  its  complete 
solution ;  and,  besides,  if  admitting  of  field  study,  the  move- 
ments of  the  lavas  in  the  great  lava-columns,  and  the  source 
or  sources  of  the  ascensive  movement. 

The  geologist  who  is  capable  of  investigating  these 
subjects  will  find  other  inquiries  rising  as  his  work  goes 
forward. 


James  D.  Dana. 


New  Haven,  Conn., 

Feb.  12,  1800. 


TABLE   OF   CONTENTS. 


part  ifirsft. 

Characteristics  op  Volcanoes. 

Page 

I.   General  Characters 1 

11.   Volcanic  Rocks,  Gases,  and  Lava-streams ,  4 

III.   Forms  of  Volcanic  Cones 11 

rV.  Methods  and  Causes  of  Volcanic  Action    ........  15 


part  ^econD* 

Contributions  from  the  Hawaiian  Islands  to  the  Science  of 

Volcanoes. 

I.   The  Island  of  Hawaii 28 

A.    KiLAUEA  . 41 

1.  KiLAUEA  before  1823 41 

2.  KiLAUEA   FROM   1823   TO    1841 45 

3.  KiLAUEA    FROM   JANUARY,    1841,    TO    1868    INCLUSIVE       ...  74 

4.  KiLAUEA    FROM    18G8    TO    1890 91 

5.  General  Summary  with  Conclusions 124 

I.   Historical  Conclusions 124 

1.  Periodicity  or  not  in  the  Discharges  of  Kilauea    ....  124 

2.  Mean  Rate  of  Elevation  of  the  Floor  of  the  Crater  after 

the  Great  Eruptions 125 

3.  Levels  of  the   Floor  after  the  Eruptions  of  1823,  1832, 

1840,  1868,  and  1886 126 

4.  Progress  in  Halema'uma'u  since  the  Eruption  of  March, 

1886 120 

6.    Other  Points  in  the  Topographic  History  of  the  Kilauea 

Region 130 

n.   Dynamical  Conclusions 141 

1.  Kilauea  a  Basalt-volcano 142 

2.  Size  of  the  Kilauea  Lava-column 151 

3.  Ordinary  Work  of  Kilauea 153 


C  TABLE   OF    CONTENTS. 

L'he  Island  of  Hawaii  {Contittued).  Page 

A.  The  Work  done  by  Vapors 154 

1.  The  Vapors  concerned  :  their  Kinds  and  Sources  .  155 

2.  The  EEfect  of  the  Expansive  Force  of  Vapors  in 

their  Escape  from  the  Liquid  Lavas  :  Projectile 

Action 158 

3.  The  Effects   of  the  Expansive   Force   of  Vapors 

within   the   Lavas.  —  Vesiculation   and  its  Me- 
chanical Effects 161 

4.  Work  of  Vapors  generated  outside  of  the  Conduit : 

Fractures,  Displacements,  and  other  Results       .  16!) 

B.  The  Ascexsive  Action  in  the  Lava-column     .  170 

C.  PREFECTS  OF  Heat .175 

D.  Hydrostatic  and  other   Gravitational  Pres- 

sure        179 

B.  Mount  Loa,  Mokuaweoweo 180 

1.  Eruptions  of  Mount  Loa  from  1832  to  1868 180 

2.  Eruptions  of  Mount  Loa  from  1868  to  1890 197 

3.  General  Summary,  avith  Conclusions 217 

1.  Times  and  Time-intervals  of  Eruptions 217 

2.  The  Ordinary  A\'ork  of  the  jNIount  Loa  Crater 222 

3.  Causes  of  the  Ordinary  Movements  within  the  Crater   .     .     .  223 

Solfataric  Action 228 

C.  Eruptions  of  Mount  Loa  and  Kilauea 228 

I.   Characteristics  and  Causes  of  Eruptions 228 

1.  Ordinary  or  Non-Explosive  Eruptions 229 

Height  and  Position  of  Outbreaks 229 

Causes  of  Eruptions        230 

Outflows  and  the  Attending  Circumstances        238 

Lateral  Cones 245 

2.  Explosive  Eruptions 245 

n.   Metamorphism  an  Effect  of  Volcanic  Conditions    .     .  254 

IIL   Form  of  Mount  Loa 256 

D.  Relations  of  Kilauea  to  Mount  Loa 258 

E.  Contrast  between  Mount  Loa  and  Volcanoes  of  the  Ve- 

suvius Type 265 

II.    Islands  of  Maui  and  Oahu 269 

A.  Island  of  Maui 269 

1.  East  Maui 273 

2.  West  INIaui 280 

3.  The  Eccentric  Form  of  the  Maui  Volcanoes   ....  281 

4.  Consolidated  Drift-sand  Ridge        282 

B.  Island  of  Oahu 282 

1.  Features,  Structure,  and  Origin  of  Oahu 285 

2.  Tufa  and  other  Lateral  Cones  of  East  Oahu     .     .     .  292 

3.  Evidence  of  Recent  Change  of  Level 302 


TABLE   OF   CONTENTS.  XI 

Page 

III.  Islands  of  Kauai  and  Nihoa 305 

A,  Kauai 305 

The  Interior  of  Volcanic  Mountains 312 

Elevation  of  the  Island 315 

B.  Nihoa,  or  Bird  Island       317 

IV.  Petrography  of  the  Hawaiian  Isla^ids,  fy  Edward  S.  Dana     .  318 

Mount  Loa  :  Lavas  of  its  Summit  Crater,  Mokuaweoweo, 

AND  of  its  Lava-streams 319 

Lava-stalactites    from    Caverns    in    Mount    Loa    Lava- 
streams 332 

Lavas  of  Kilauea 342 

Relation   between   the   Rocks  of  the  Summit  Crater  of 

Mount  Loa  and  those  of  Kilauea 347 

Lavas  of  Maui 349 

Lavas  of  Oahu 353 


part  ^l)iri3. 

Volcanoes  and  Deep-sea  Topography. 

The  Bathymetric  Map,  and  the  General  Features  of  the  Oceanic 

Depression  displayed  by  it 358 

The  Feature-lines  of  the  Oceanic  and  Bordering  Lands     .     .     .  360 

Facts  bearing  on  the  Origin  of  the  Deep-sea  Troughs    ....  363 

A.  Facts  apparently  favoring  a  Volcanic  Origin 363 

B.  Facts  from  the  Vicinity  of  Volcanic  Regions  apparently  not  referable  to 

a  Volcanic  Origin 365 

C.  Facts  from  Regions  not  Volcanic  which  are  unfavorable  to  the  Idea  of 

a  Volcanic  Origin 366 

D.  Arrangement  of  the  Deep-sea  Troughs  in  the  Halves  of  the  Oceans 

pointing  to  some  other  than  a  Volcanic  Origin 369 

Conclusions 370 


part  iTourt!), 

Denudation    of    Volcanic    Islands  ;    Its    Amount    a    Mark    op 
Age 373 

Index       393 


LIST    OF    PLATES. 


Page 
I.     Map  of  Hawaii,  reduced  from  the  Map  of  the  Hawaiian  Govern- 
ment   Survey Frontispiece 

II.     Sketch  of  the  Crater  of  Kilauea  in  1840,  by  J.  Drayton      ....  33 
in.     Map  of   Kilauea,  by  Emerson  and  Dodge,  of  the  Hawaiian  Govern- 
ment Survey 98 

IV.     View  of  North  Part  of  Debris-cone  in  Halema'uma'u.  January,  1887  103 

V.     View  of  Debris-cone  in  October,  1886 107 

VI.     View  of  Debris-cone  in  the  Spring  of  1887 Ill 

VH.     Lava-floor  of  Kilauea H*^' 

VIII.     View  of  Debris-cone  of  September,  1887 -1-1 

IX.     Map  of  Kilauea,  combining  Part  of  Wilkes's  and  Brigham's  Maps 

with  that  of  Plate  III 140 

X.     Map  of  Mokuaweoweo,  by  J-  M.  Alexander     ........  181 

XI.     Lava-cascade  in  the  Lava-stream  of  1880-1881 207 

XII.     Lava-fountain  of  January,  1887 213 

XIII.  Map  of  the  Island  of  Maui,  from  the  Map  of  the  Hawaiian  Govern- 

ment Survey 271 

XIV.  ;Map  of  the  Island  of  Oahu,  from  the  ]\Iap  of  the  Hawaiian  Govern- 

ment Survey,  witli  Views  of  some  of  its  Tufa-cones        ....  283 
XV.     Lava-stalactites  from  a  Cavern  in  the  Stream  of  1880-1881,  near 

Hilo 333 

XVI.     Bathymetric  Map  of  the  Oceans     , 355 


LIST   OF   ILLUSTRATIONS   IN   THE   TEXT. 


Page 

Aa  Lava-field 10 

Map  of  the  Hawaiian  Islands 26 

Sketch  of  the  South  End  of  Kilauea,  by  Ellis,  engraved  by  Mr.  Jocelyn  of 

New  Haven,  Conn 46 

Ellis's  Sketch,  as  engraved  in  England 47 

Ellis's  Sketch,  as  engraved  for  his  "  Polynesian  Researches  " 50 

Map  of  Kilauea,  by  Lieutenant  INIalden,  R.X 51 

View  of  Kilauea,  by  R.  Danijiier 52 

View  of  South  End  of  Kilauea,  by  Ca[itains  Chase  and  Parker 60 

Map  of  Part  of  Hawaii,  illustrating  the  Eruption  of  1840,  from  the  Map 

of  Hawaii  of   the  United  States  Exploring  Expedition  under  Captain 

Wilkes , 62 

Tufa  Hills  of  Nanawale,  1840,  from  Drawing  by  the  Author     .....  04 

Map  of  Kilauea  in  1840,  by  Captain  Wilkes 06 

Driblet-cone  in  Kilauea,  November,  1840 71 

Map  of  Kilauea,  by  T.  Coan,  illustrating  the  Overflow  of  Lava  and  Canals 

of  1844 75 

Map  of  Kilauea  in  1846,  by  C.  S.  Lyman 79 

Map  of  Kilauea  in  1885,  by  William  T.  Brigham 84 

Driblet-cone  of  1864,  by  William  T.  Brigham 85 

View  of  Kilauea  in  1864,  from  a  Painting  by  Mr.  Perry 87 

Trunk  of  Tree  encased  by  Lava 91 

Mapof  Kilauea  in  1874,  by  J.  M.  Lydgate 93 

Floating  Island  in  Halema'uma'u,  Kilauea    .  * 99 

Floating  Island  Stranded 100 

Map  of  Halema'uma'u  and  South  End  of  Kilauea  in  1886,  by  J.  S.  Emerson  102 

View  of  Debris-cone  in  Halema'uma'u,  August,  1887 113 

Wrinkles  or  Tapestry-like  Folds  on  the  Surface  of  a  Lava-lake       .     .     .     .  117 

Dome-like  Elevation  of  Lava  in  Kilauea          118 

Map  and  Sections  of  Halema'uma'u  and  Cone 120 

Sections  of  the  Crater  of  Kilauea,  1823  to  1886 127 

Sections  of  Halema'uma'u,  by  F.  S.  Dodge 129 

Map  of  Kilauea,  by  Captain  Wilkes 133 

Map  of  Kilauea,  by  William  T.  Brigham       .     , 134 


XVI  LIST   OF   ILLUSTRATIONS   IN   THE   TEXT. 

Page 

Map  of  Kilauea,  by  C.  S.  Lyman 139 

Magnified  Views  of  Pele's  Hair,  by  C.  F.  W.  Krukenberg 161 

Thread-lace  Scoria 164,  165 

Diagram  illustrating  the  Origin  of  Lyman's  Ridge  .........     173 

Map  of  Mokuaweoweo,  of  the  Wilkes  Exjjloring  Expedition 184 

Source  of  Lava-stream  of  1880 205 

Aa  Lava-stream 241 

Tarawera  Geyser  and  Volcanic  Region,  New  Zealand 247 

Diagram  showing  the  Combinations  of  Volcanoes  in  the  Hawaiian  Islands     259 

Map  of  the  Hawaiian  Islands 261 

Cones  of  Kaneohe  Point,  Oahu 300 

View  showing  the  Western  Moimtains  of  Oahu  buried  at  Base  by  Lavas 

from  Eastern  Oahu 301 

Kahuku  Bluffs  of  Coral-rock,  Oahu 302,  303 

Koloa  Region  of  Craters  on  Kauai „     .     .     .     309 

Bluff  of  Drift-sands,  Kauai 316 

Feathery  Forms  of  Augite  in  Mount  Loa  Lavas 321,  322 

Chrysolite  Crystals  of  IMount  Loa  Lavas .     325 

Microlites  of  Lavas .     331 

Enlarged  Views  of  Lava-stalactites 336,  337 

Sections  of  the  Stalactites  and  Outline  of  a  Crystal  of  Feldspar      ....     338 

Outline  of  a  Twin  Crystal  of  Feldspar  from  Maui 352 

IMap  of  Tahiti 375 

The  Crown  at  the  Head  of  Papiete  Valley,  Tahiti   .........     376 

Outline  Sketch  of  Orohena  and  Pitohiti 378 

Diagram  illustrating  River  Erosion,  New  South  Wales 390 


CHARACTERISTICS   OF   VOLCANOES. 


pan  fxY^t 

VOLCANOES. 


I.    GENERAL    CHARACTERS. 

A  VOLCANO  is  a  mountain  or  hill,  more  or  less  conical 
in  shape,  which  has  a  nearly  central  cavity  at  top, 
called  a  crater,  and  which  discharges  at  times  melted  rock, 
called  lava,  and  also  vapors  or  gases.  The  lava  either  Jioivs 
down  this  or  that  side  of  the  mountain  in  streams,  of  is 
projected  into  the  air  to  fall  around  the  vent,  or  lava-source, 
in  fragments.  The  cooled  fragments  from  a  projectile  dis- 
charge are  called  volcanic  cinders,  but  the  finer  part,  often, 
volcanic  ashes  ;  if  not  cooled  on  the  descent,  they  are  drops 
or  driblets. 

Since  the  accumulation  of  rock-material,  whether  due  to 
descending  streams  of  lava  or  to  projected  fragments,  is 
made  around  a  central  lava-source,  or  is  j^eincentric  ^  in  depo- 
sition, the  hill  or  mountain  built  up  takes  the  form  of  a 
more  or  less  regular  cone ;  and  a  crater  exists  in  its  top  be- 
cause of  the  discharges  of  lava  and  vapor  from  the  lava- 
source  within  or  beneath  it. 

A  volcano,  as  long  as  it  is  active,  has  thus  —  (1)  its  vapor 
or  gaseous  discharges;  (2)  its  flowing  lava-discharges;  and 
(3)  its  projectile  discharges. 

^  Derived  from  the  Greek  rrepi,  about,  ami  Kivrpov,  a  centre. 


2  CHARACTERISTICS   OF   VOLCANOES. 

When  discharges  of  liquid  lava  take  place,  or  unusual  pro- 
jectile discharges,  or  both  together,  the  volcano  is  in  erup- 
tion. Such  eruptions  result  in  emptying  or  deepening  the 
crater.  They  may  occur  at  intervals  of  three  or  four  years, 
but  often  scores  intervene.  In  the  interval  between  erup- 
tions, the  deepened  crater  may  be  for  a  while  wholly  quiet. 
But  sooner  or  later,  in  the  active  volcano,  vapors  begin  to 
rise  from  fissures,  and  small  lava-flows  and  projectile  dis- 
charges take  place  over  the  bottom ;  and  this  continues, 
perhaps  with  interruptions,  until  ready  for  another  out- 
break. 

In  projectile  discharges  the  height  to  which  the  fragments 
are  projected  into  the  air  may  be  several  thousands  of  feet 
during  a  great  eruption,  and  hundreds  or  scores  of  feet  in 
the  interval.  But  in  volcanoes  of  the  Hawaiian  kind  the 
lava  is  ordinarily  thrown  to  so  little  height  that  the  frag- 
ments are  not  cooled  on  the  descent,  and  no  cinders  or 
cinder-cones  are  made ;  they  are  thrown  up  like  the  small 
jets  over  a  boiling  liquid.  Yet  even  in  such  volcanoes  lat- 
eral and  terminal  cinder-cones  under  some  circumstances  are 
formed. 

At  an  eruption  the  discharged  lava  may  flow  from  the 
summit  crater  in  great  streams  down  the  mountain ;  or,  sec- 
ondly, it  may  escape  to  the  surface  of  the  cone  through  fis- 
sures in  the  mountain's  sides,  made  by  the  eruptive  forces, 
and  thence  spread  away  in  streams  ;  or,  thirdly,  it  may  flow 
oft'  through  fissures  into  cavities  between  the  old  lava-streams 
of  the  mountain,  or  force  its  way  between  the  layers,  and 
not  show  itself  anywhere  at  the  surface  ;  or,  fourthly,  it  may 
only  fill  fissures  made  below  by  the  volcanic  action.  Dis- 
charges of  the  first  kind  are  superjluent  discharges ;  those 
of  the  second,  effluent,  or  out  of  fissures  ;  those  of  the  third, 
interjiuent.  But  for  the  third  and  fourth  kinds  all  that  can 
commonly  be  said  is  expressed  in  the  word  subterranean. 
Superfluent   discharges   are   probably  the  prevailing  kind  at 


CHARACTERISTICS  OF  VOLCANOES.  3 

the  comnienceiiient  of  a  volcano,  the  lavas  then  pouring  out 
copiously  from  the  vent  or  over  the  brim  of  the  crater.  But 
at  the  present  time  the  discharges  are  effluent,  or  from  fis- 
sures, though  often  also  subterranean. 

The  outflow  from  fissures  may  take  place  at  any  height  on 
the  mountain,  from  the  top  to  the  base,  and  also  beneath  the 
sea-level.^  If  the  latter,  the  eruptions  are  auhmarine  ;  if  the 
former,  suhaerial. 

The  fissures  from  which  outflows  take  place  are  sometimes 
so  wide  at  some  spots  as  to  pour  out  the  lavas  from  these 
places  for  weeks,  so  as  thereby  to  make  cones  of  lava  ;  or 
if  the  lava  ceases  to  flow  out,  they  may  have  projectile  dis- 
charges for  a  time  and  make  cinder-cones.  In  either  case 
a  line  of  cones  may  be  formed  on  a  fissure.  Such  cones 
while  in  action  are  true  volcanoes  in  all  their  characters. 
They  are  distinguished  as  the  lateral  cones  of  a  volcano 
or  volcanic  mountain.'^  The  extinct  lateral  cones  of  a  sub- 
marine eruption  often  stand  as  islands,  or  make  shoals,  off 
a  coast. 

The  regions  of  exhausted  volcanoes,  and  sometimes  the 
borders  of  active  volcanoes,  may  have  fissures  that  give  out 
hot  air,  vapors,  and  gases  in  a  quiet  vv^ay,  and  that  make  de- 
posits of  sulphur,  alum,  gypsum,  or  other  minerals  about  the 
sides  of  the  fissures  or  in  the  soil.  Such  regions  are  called 
solfataras,  from  the  Italian  for  sulphur ;  and  the  vapor- 
emitting  fissures  are  called  fumaroles,  from  the  Latin  for 
smohe.  The  heat  of  fumaroles  may  be  as  high  as  750°  F. 
Lava-caverns  in  and  about  craters  often  receive  hot  vapors, 
and  have  similar  incrustations  ;  and  sometimes  they  are 
hung  with  lava-stalactites. 

^  The  sources  and  courses  of  several  great  lava-streams  are  shown  on  Plate  I. 
(trontispiece),  the  clotted  belts  representing  the  streams. 

^  Many  lateral  cones  are  shown  on  the  map  of  Maui,  Platu  XII. 


CHARACTERISTICS   OF   VOLCANOES. 


II.    VOLCANIC    ROCKS,    GASES,    AND    LAVA-STREAMS. 

1.  Volcanic  Rocks.  —  Lava  is  a  general  term  for  any 
rock  of  a  lava-stream.  It  may  be  very  compact.  —  that  is, 
without  a  cellule  ;  or  it  may  contain  air-cavities  or  vesicles 
that  were  made  by  expanding  vapor  while  the  lava  was  still 
liquid,  and  so  be  a  vesicular  lava.  But  vesicular  lava  may 
be  very  openly  vesicular,  like  a  furnace  slag,  and  then  it 
is  scoriaceous  lava  ;  or  it  may  be  made  chiefly  of  vesicles, 
and  then  it  is  a  scoria,  the  scum  or  froth  of  the  liquid 
lava. 

Lava,  on  cooling  rapidly,  sometimes  becomes  glass,  or  has 
a  thin  glassy  crust ;  but  on  cooling  slowly^  the  same  material 
may  become  stone,  by  the  conversion  of  glass  into  stony  par- 
ticles, which  are  the  constituent  minerals  of  the  lava.  The 
lighter  scoria  of  a  volcano  is  mostly  glass.  Generally,  but 
not  always,  minute  portions  of  the  glass  remain  in  the  most 
solid  lavas.  By  extreme  slowness  of  cooling,  such  as  may 
occur  in  Nature  in  the  interior  of  great  igneous  masses  or 
under  a  deep  covering  of  rocks,  the  texture  of  lava  may  be- 
come coarsely  crystalline,  like  granite  or  syenyte  ;  so  that, 
although  granite  has  little  resemblance  to  ordinary  lava,  it 
may  be  as  truly  an  igneous  rock  as  the  lavas  of  Kilauea  or 
Vesuvius,  and,  as  Judd,  Hague,  Iddings,  and  others  have 
shown,  be  part  of  the  same  eruption  with  scoriaceous  lavas. ^ 

The  more  common  kinds  of  lava  consist  as  follows  :  — 

I.  Of  feldspar,  as  the  chief  ingredient. 

II.  Of  a  feldspar,  with  one  of  the  two  iron-bearing  min- 
erals, augite,  hornblende. 

I.    Lavas  consisting  chiefly  of  a  Feldspar.  —  These 

lavas  are  generally  light  in  color  and  light  in  weight.     The 

specific  gravity  is  2.5    to    2.8.     The  feldspar   is    ordinarily 
orthoclase  or  potash-feldspar. 

^  See  page  314. 


CHARACTERISTICS   OP^   VOLCANOES.  5 

A  coinmun  kind,  breaking  with  a  rough  surface  of  fracture 
and  little  lustre,  is  called  Trachyte  ;  some  black  hornblende 
crystals  are  often  present,  and  tables  of  feldspar  called  sani- 
din,  and  rarely  small  crystals  of  black  or  brown  mica.  If  it 
contains  quartz  dissemmated  through  it,  visibly  or  not,  it  is 
named  Rhyolyte  (from  the  Greek  for  to  flovj)  or  Quartz- 
trachyte  ;  when  in  the  form  of  glass,  it  is  Obsidian  ;  when 
partly  glassy,  and  therefore  pitch-like  or  resin-like  in  lustre, 
it  is  Pitchstone  ;  when  a  fine  light  scoria,  Pumice. 

A  rock  having  the  composition  of  trachyte  or  quartz- 
trachyte,  but  smooth,  flint-like,  in  surface  of  fracture,  is  called 
Felsyte  ;  and  wdien  coarsely  crystalline,  the  feldspar  being 
in  crystalline  grains,  and  the  quartz  in  visible  grains,  it  is 
called  Granulyte  ;  and  the  latter,  when  mica  is  present,  is 
the  common  crystalline  rock  called  Granite."  A  felsyte 
spotted  with  whitish  feldspar  crystals  is  a  variety  of  Por- 
pliyi-y,  or  a  j^orphyritic  Felsyte. 

Leucite,  a  potash-bearing  mineral  related  in  composition  to 
orthoclase,  is  prominent  in  some  volcanic  rocks.  Its  crystals 
are  twenty-four-sided  garnet-like  forms.  It  is  called  leucite, 
from  its  whitish  color.  A  leucite-rock  occurs  in  Wyoming, 
and  another  kind  is  common  at  Vesuvius. 

II.  Lavas  consisting  of  a  Feldspae  and  other  Ingre- 
dients. —  In  the  other  common  igneous  rocks  the  feldspar 
may  be  (1)  ortliodase ;  (2)  oligoclase,  which  contains  the 
alkalies,  soda  and  lime,  with  more  soda  than  lime,  —  or  the 
related  andesine  ;  or  (3)  labradorite,  which  also  is  a  soda- 
lime  feldspar,  but  with  more  lime  than  soda. 

1 .  Tlte  Orthoclnse  and  Hornblende  or  Augite  Rocks.  —  These 
rocks  are  Syenyte,  Quartz-syenyte,  Augite-syenyte,  and 
some  others  wdiich  are  not  among  the  rocks  of  ordinary 
lavas. 

Leucite  and  augite  are  the  chief  constituents  of  Amphi- 
genyte  (or  Leucitophyre),  tbe  rock  of  the  Vesuvian  lavas 
just  alluded  to. 


6  CHARACTERISTICS   OF   VOLCANOES. 

2.  Oligoclase  Rocks.  —  A  coiniiion  lava  of  this  group,  of 
light  to  dark  gray  and  greenish  color,  is  called  Andesyte, 
from  the  Andes.  It  consists  of  oligoclase  or  andesine  and 
hornblende.  A  related  rock,  Angite-andesyte,  consists  chiefly 
of  oligoclase  and  aiigite  ;  and  where  hypersthene,  a  mineral 
related  to  angite,  replaces  the  latter,  another  variety  is 
produced. 

When  a  rock  of  the  composition  of  andesyte  has  a  com- 
pact or  a  crystalline-granular  texture  with  none  of  the  aspect 
of  a  lava,  it  is  called  Dioryte.  Its  common  colors  vary  from 
whitish  to  greenish-black.  A  compact  red  dioryte,  with  part 
of  the  feldspar  in  small  whitish  crystals,  is  the  Red  Porphyry 
of  the  ancients. 

3.  Labradorite  Rocks.  —  Basalt  and  Doleryte  are  common 
lavas  of  this  group.  Doleryte  (or  Diabase)  consists  of  la1)ra- 
dorite  and  augite,  with  more  or  less  magnetite,  and  is  a 
heavy  dark-colored  rock,  with  the  specific  gravity  2.9  to  3. 
Basalt  is  the  same  rock  ;  but  it  contains,  in  addition,  chryso- 
lite (olivine),  a  mineral  looking  much  like  grains  of  green 
bottle-glass,  with  the  specific  gravity  2.D  to  3.2.  The  angite 
is  not  unfreqnently  in  distinct  black  crystals,  and  the  kahra- 
dorite  in  white  or  whitish  crystals.  These  rocks  are  com- 
monly very  fine-grained,  and  vary  from  compact  to  vesiculated, 
scoriaceous,  and  scoria.  But  doleryte  and  basalt  vary  also, 
on  the  other  side,  without  cliange  of  composition,  to  coarsely 
crystalline  rocks,  the  common  Ivind  of  which  is  called  Gabl)ro. 

In  another  labradorite  sei'ies  the  rocks  consist  of  labra- 
dorite and  hornblende.  They  resemble  dioryte,  and  one  kind 
is  called  Labradioryte.  The  green  porphyry,  or  oriental  rcrd 
antique  of  the  ancients,  is  a  handsome  porphyritic  variety  of 
the  rock. 

Other  igneous  rocks  have  anorthite  or  nephelite,  as  prom- 
inent constituents  ;  or  they  may  consist  chiefly  of  augite, 
hornblende,  or  chrysolite.  On  this  subject  of  volcanic  rocks 
reference  shoidd  be  made  to  works  on  petrology. 


CHARACTERISTICS   OF   VOLCANOES.  7 

The  most  fusible  of  coniiuon  lavas  is  doleryte  or  basalt, 
the  temperature  of  fusion  being  between  2000°  F.  and 
2500°  F.  Trachyte  and  rhyolyte  are  among  the  least  fusi- 
l^le,  and  andesyte  is  intermediate  in  degree  of  fusibilit3^ 

A  columnar  or  "basaltic"  structure,  more  or  less  perfect, 
is  very  common  hi  solidified  lava-streams,  as  a  result  of  con- 
traction on  cooling.  Even  the  most  recent  lavas  may  exhibit 
it.  It  is  most  common  in  basaltic  rocks,  but  occurs  also  in 
other  kinds,  even  in  obsidian  or  volcanic  glass,  as  described 
by  Iddings  from  the  Yellowstone  Park. 

Tufa.  —  Tufa,  or  tuff,  as  its  method  of  formation  implies, 
is  nothing  but  a  fragmental  rock  of  volcanic  origin, — 
a  kind  of  argillaceous  sandstone  made  out  of  volcanic 
ashes  usually  half  decomposed.  Its  colors  vary  from  gray 
to  yellow,  brown,  and  reddish-brown.  The  brown  and 
brownish-yellow  colors  depend  on  the  hydrous  iron-oxide 
(Fe203  +  Aq)  present  as  a  result  of  alteration.  It  some- 
times has  a  lustre  almost  like  that  of  a  resin,  as  is  well  ex- 
emplified at  the  quarry  on  Punchbowl,  Oahu.  The  material, 
which  was  originally  like  powdered  lava  in  composition,  has 
been  changed  by  the  heat  and  moisture.  The  rock  in  this 
state  is  called  j)ala(jonite.  Besides  the  finer  kinds,  there 
are  also  coarse  conglomerates  among  fras-mental  volcanic 
rocks. 

The  "  cinders,"  or  scoria,  of  a  cinder-cone  are  often  of  a 
bright  red  color ;  and  this  is  due  to  surface  decomposition 
of  the  augite  producing  the  red  iron-oxide  (hematite  or 
red  ochre,  Fe203).  When  the  decomposition  goes  on  in  the 
presence  of  moisture,  the  color  is  usually  yellowish-brown, 
from  the  production  of  the  hydrous  oxide  above  alluded  to 
(Fe^O;^  -j-  Aq,  or  limonite). 

2.  Yapoes  or  Gase.s.  —  The  vapors  which  are  emitted  by 
the  liquid  lavas  of  the  volcano  are  at  least  ninety-nine  per 
cent  steam,  or  vapor  of  water.  There  is  never  any  true 
smoke.     The  amount  of  vapor  given  out  is  large  in  periods 


8  CHARACTERISTICS   OF   VOLCANOES. 

of  special  activity,  and  clouds  consequently  are  made  over 
the  mountain  in  the  cool  air  above. 

Sulphurous  acid  (SO2)  is  probably  the  most  common  of  the 
vapors  next  to  that  of  water.  It  has  the  smell  of  burning 
sulphur.  H3drogen  is  one  of  the  gases  that  escape  from 
the  liquid  lava,  and  its  occurrence  is  attributed  to  the  disso- 
ciation of  the  elements  of  water  (HgO)  by  the  extreme  heat.^ 
Chlorine  is  emitted  if  sea-waters  get  access  to  the  lava-col- 
umn, it  being  supplied  in  that  case  by  the  common  salt  of 
the  sea  (NaCl)  ;  and  when  present,  chlorides  occur  as  in- 
crustations on  the  lavas,  among  which  are  common  salt, 
iron  chloride,  and  others.  Flames  attributed  to  the  com- 
bustion of  free  hydrogen  have  been  observed. 

Other  gases  are  only  very  sparingly  present  in  the  liquid 
lavas,  but  occur  in  solfataras  or  fumaroles.  Hydrogen  Sul- 
phide (H2S),  or  sulphuretted  hydrogen,  is  sometimes  detected, 
but  not  where  the  action  is  intense.  Carbonic  acid  (CO2) 
may  be  given  out  if  any  limestone  exists  beneath  the  vol- 
cano. Hydrochloric  acid  (HCl)  is  another  of  the  gases  from 
the  hotter  fumaroles ;  and  nitrogen  is  sometimes  present. 

Pyrite  and  marcasite,  iron  sulphides  (FeS2),  present  in 
minute  quantities  in  the  rocks  of  the  depths  below  the 
crater,  are  supposed  to  be  the  common  source  of  the  sul- 
phur and  sulphur  gases. 

Various  deposits  occur  in  solfataras  and  in  caverns  about 
volcanoes,  produced  by  the  escaping  gases,  of  which  the  most 
common  are  the  sulphates,  —  gypsum  (hydrous  calcium  sul- 
phate), alums  (hydrous  aluminum  sulphate,  and  aluminum- 
sodium  sulphate),  glauber  salt  (hydrous  sodium  sulphate), 
which  is  common  in  Hawaiian  hot  caverns ;  occasionally 
hydrous  copper  sulphate  or  blue  vitriol.  The  gases  decom- 
pose the  rocks  to  earth.  Incrustations  of  sulphur  are  com- 
mon, and  occasionally  large  deposits  are  made. 

^  Foiique,  Santorin  et  ses  Eruptions,  Paris,  1879;  Siemens,  Monatsb.  K.  Preuss. 
Akad.,  1878,  from  investigations  at  Vesuvius. 


CHARACTERISTICS    OF   VOLCANOES.  9 

3.  Lava-streams.  —  Lava-streams  are  of  two  kinds.  (1) 
There  is  the  ordinary  smooth-surfaced  lava  of  volcanoes.  It 
is  the  pahoeUoe  of  Hawaii,  the  term  signifying  ''  having  a 
satin-like  aspect."  The  surface  of  the  lava  shows,  by  the 
fine  and  coarse  flow-lines  over  it,  that  it  cooled  as  it  flowed. 
'Through  one  means  and  another  the  surface  is  usually  un- 
even, being  often  wrinkled,  twisted,  ropy,  billowy,  hummocky, 
knobbed,  and  often  much  fractured.  Plate  VIL  shows  some- 
thing of  the  uneven  character,  but  not  the  larger  irregularities. 
The  streams  have  sometimes  ii  Arm  glassy  exterior  half  an 
inch  or  less  in  thickness.  When  lava  overflows  from  a 
boiling  lava-lake,  it  cari'ies  jilong  a  surface  scum  one  to 
three  or  four  inches  tliick,  which  is  a  glassy  scoria,  usually 
easily  separable  from  the  more  solid  and  chief  part  of  the 
lava-stream. 

The  crusting  over  of  a  stream  while  it  is  still  flowing, 
owing  to  contact  with  the  air  above,  results  in  the  leaving 
of  empty  tunnel-like  caverns,  which  are  sometimes  hung  w^ith 
stalactites. 

(2)  The  other  most  prominent  kind  of  lava-stream  is  the 
cm.  The  aa  streams  have  no  upper  flow-like  surface  ;  tliey 
are  beds  of  broken  up  lava,  the  breaking  of  which  occurred 
during  the  flow.  They  consist  of  detached  masses  of  irregu- 
lar shapes,  confusedly  piled  together  to  a  height  sometimes 
of  twenty-five  to  forty  feet  above  the  general  surface.  The 
size  of  the  masses  is  from  an  inch  in  diameter  to  ten  feet 
and  more.  The  lava  is  compact,  usually  less  vesiculated 
than  the  pahoehoe,  not  scoriaceous ;  but  exteriorly  it  is 
roughly  cavernous,  horridly  jagged,  with  projections  often 
a  foot  or  more  long  that  are  bristled  all  over  with  points  and 
angles.  In  some  cases  ragged  spaces  extend  along  planes 
through  the  large  masses,  like  those  of  the  exterior  ;  but  in 
these,  as  in  other  parts,  it  is  evident  that  the  agency  was 
tearing  and  up-ploughing  and  cavity-making  in  its  action, 
and   not  vesiciflating.       Occasionally   (as   well    seen   west  of 


10 


CHARACTERISTICS   OF   VOLCANOES. 


Piiiialuu,  on  southern  Hawaii)  great  slab-like  masses  of  very 
compact  rock,  twenty  feet  or  more  long,  eight  feet  high,  and 
three  to  ten  inches  thick,  stand  vertically  together,  with  a 
curving  over  at  top,  somewhat  like  gigantic  shavings.  Sim- 
ilar slabs  are  mentioned,  as  occurring  on  the  Kilauea  lava- 
stream  of  1840,  on  page  63. 


The  above  figure  represents  the  features  of  such  a  stream. 
The  title  of  such  piles  of  blocks  to  the  name  of  a  stream 
w^ould  not  be  admitted  were  it  not  proved  that  they  are 
formed  during  the  progress  of  a  lava-flow ;  that  a  lava- 
stream  may  change  from  the  suiooth-flowing  or  pahoehoe  con- 
dition to  the  act,  and  back  again  to  the  smooth-flowing  ;  and 
that  the  same  vent  may  give  out  at  one  and  the  same  time  a 
smooth-flowing  stream  in  one  direction  and  an  aa  stream  in 
another.  Lava  of  the  aa  kind  occurs  at  Vesuvius,  as  well 
described  by  Sir  William  Hamilton  in  1779,  and  later  by 
•other  authors. 

The  aa  streams  are  remarkable  also  for  the  presence  of 
lava-halls  of  concentric  structure  that  have  been  wTongly 
called  bombs.  These  lava-balls  are  smoothish  exteriorly, 
more  or  less  rounded  and  bowlder-like,  and  vary  in  size  from 
an  inch  or  less  to  ten  feet  and  more.  One  of  them  is  repre- 
sented in  the  aa  picture,  at  the  top  to  the  right. 

Some  of  these  lava-balls  have,  outside,  a  crust  of  hard 
lava,  and,  inside,  fragments  of  scoria  or  grains  of  chrysolite 
(olivine)  ;  others  consist  of  concentric  shells,  hard  and  scori- 


CHARACTERISTICS   OF  VOLCANOES.  11 

aceous  shells  alternating  with  one  another.  One  on  Hawaii 
near  Punalim  was  found  to  have  a  nucleus  of  scoria  eighteen 
inches  in  diameter,  and  around  this  successively  a  stony 
shell  of  three  inches,  a  scoriaceous  layer  of  one  to  two  inches, 
a  stony  shell  of  four  to  five  inches,  and  then  outside  a  rough 
lava  shell  six  inches  thick.  One  of  large  size,  broken  open  on 
one  side,  had  had  its  inside  filling  of  scoria  worked  out  by  the 
natives,  and  so  made  into  a  small  cave.^  A  common  size  on 
Hawaii  is  three  to  five  feet  in  diameter ;  but  one  enor- 
mous lava-ball,  in  the  aa  field  west  of  Punaluu,  measured 
24  X  12  X  9  feet  in  its  extreme  dimensions,  and  contained 
at  least  a  thousand  cubic  feet.  Enough  of  its  hard  outer 
shell  was  pealed  off  to  ascertain  that  the  second  layer  was 
quite  vesicular  or  scoriaceous,  and  the  next  layer  inside  hard 
basalt  again.  These  Hawaiian  lava-balls  lie  in  the  midst  of 
the  other  blocks  of  the  an  stream,  proving  that  all  had  a 
common  origin,  and  tliat  they  are  not  ijrqjected  homhSy  and 
hence  properly  not  bombs  at  all. 

The  so-called  '*  l)ombs  "  of  Vesuvius  have  been  shown  in- 
dependently by  Dr.  Johnston-Lavis,  of  Naples,  to  have  had 
essentially  the  same  origin.^ 


III.  FORMS  OP  VOLCANIC  CONES. 

The  volcanic  cone  or  mountain  takes  its  shape  partly  from 
the  nature  and  condition  of  the  material  of  whicli  it  is  made, 
partly  from  the  position  of  the  places  of  outflow,  and  partly 
from  the  copiousness  of  the  flow.  Other  causes  —  as  sul)- 
sidences  and  uplifts  —  may  modify  the  forms  ;  but  the  forms 
not  so  modified  are  those  here  considered. 

If  the  lava  were  as  liquid  as  water,  cones  of  sensible  slope 

1  American  .Journal  of  Science,  1887,  3d  series,  xxxiv.  364. 

^  Johnston-Lavis,  in  a  paper  on  "  The  Fragmentary  Ejectanienta  of  Volcanoes," 
in  the  Proceedings  of  the  Geologists'  Association,  London,  vol.  ix.  no.  6,  and  Ameri- 
can Journal  of  Science,  1888,  xxxvi.  103. 


12  CHARACTERISTICS   OF   VOLCANOES. 

would  be  impossible.  Lava  has  various  grades  of  viscidity 
or  liquidity  ;  and  in  the  most  liquid  stage  —  that  which  ex- 
ists when  the  heat  is  at  or  above  the  fusing-point  of  the 
essential  ingredients  —  there  is  still  a  degree  of  viscidity  or 
cohesion  sufficient  to  cause  some  resistance  to  free  move- 
ment, and  hence  a  slope  in  the  upper  surface  of  the  flowing 
stream. 

From  this  stage  of  most  perfect  mobility  there  may  be  all 
grades  of  viscidity,  in  consequence  of  partial  cooling,  —  cool- 
ing producing  incipient  and  finally  complete  solidification. 

If  melted  beeswax  were  poured  out  on  a  fiat  surface  while 
heated  above  the  fusing-point,  it  would  flow  off  at  a  very 
small,  angle  ;  and  a  very  copious  flow  would  be  impeded 
neither  by  cooling  below  against  a  cold  surface  nor  above 
against  the  air.  But  if  the  temperature  were  below  that  of 
fusion,  the  liquid  beeswax  would  be  pasty,  and  the  angle  of 
flow  or  of  the  pitch  of  the  upper  surface  wolild  increase  with 
decrease  of  temperature.  Copious  streams  would  have  the 
smaller  angle  ;  while  small  streams  would  give  ^increased 
pitch,  and  drops  might  make  a  vertical  column. 

The  facts  are  the  same  in  principle  with  lava.  Basaltic 
lava  in  the  state  of  most  perfect  liquidity  flows  at  an 
angle  much  less  than  that  of  1°,  as  is  shown  by  the 
surfaces  of  the  great  basaltic  floods  in  the  Snake  River 
region  and  others  on  the  Pacific  border  slope  of  North 
America,  as  well  as  1)y  the  occurrence  of  a  pitch  of  1"  and 
less  in  the  lava-streams  of  some  of  the  Hawaiian  Islands. 
Copious  flows  —  such  as  have  occurred  in  the  earlier  dis- 
charges of  a  volcanic  vent  —  may  therefore  make  basaltic 
cones  of  I"  and  less.  But  the  flows  of  modern  volcanoes 
are  not  ordinarily  of  this  copious  kind.  The  lava  of  an 
eruption  is  discharged  in  portions  at  intervals  of  hours  or 
days  or  weeks,  and  the  streams  become  cooled  at  bottom 
and  cooled  at  top,  so  that  only  the  interior  flows  on  in  a 
kind  of  tube  or  tunnel,  and  this,  as  it  emerges   below,  takes 


CHARACTERISTICS  OF  VOLCANOES.  13 

its  chances  of  cooling.  The  streams  are  narrow  strips  down 
the  cone.  They  come  out  usually  from  fissures,  and  at  all 
heights  between  the  top  and  the  bottom.  The  resulting 
angle  for  a  basalt-volcano  becomes  thereby  1°  to  10°,  and 
rises  often  to  90°  in  the  driblet  cone. 

With  the  less  fusible  lava  the  cones  are  of  steeper  angle 
than  with  basalt,  since  the  high  temperature  of  fusion  gen- 
erally fails  of  being  supplied  from  the  depths  below,  and  is 
more  easily  lost  by  cooling;  and  the  lava  therefore  is  com- 
monly more  or  less  pasty.  The  andesyte  cones  of  western 
North  and  South  America  are  25°  to  34°  in  slope. 

Since  a  cone  diminishes  in  diameter  upward,  a  flow  of  lava 
from  near  the  summit  liaving  like  width  throughout  would 
cover  a  much  larger  part  of  the  circumference  in  the  upper 
part  than  in  the  lower.  The  part  of  the  cone  below  would 
require  in  fact  a  great  number  of  ordinary  streams  to  make 
one  coat  over  the  surface.  The  consequence  of  this  condition 
is  that  such  discharges  make  the  cone  steeper  above,  and  give 
it  a  concave  outline.  But  if  the  flows  commence  for  the  most 
part  a  little  below  the  summit,  from  an  eighth  to  a  sixth 
of  the  height,  the  upper  part  would  be  widened  and  the  cone 
take  the  form  of  a  low  dome,  like  Mount  Loa  ;  or  if  the 
streams  come  from  fissures  in  the  lower  part  of  the  cone  and 
spread  beyond  the  base,  the  cone  will  be  flattened  below,  and 
the  lower  part  of  the  profile  will  be  made  concave. 

The  possible  slopes  of  the  sides  of  cinder-cones  may  be 
learned  from  a  very  simple  experiment.  If  circles  half  an 
inch  apart  are  described  about  a  centre  on  a  large  card,  and 
a  slender  graduated  rod  is  inserted  vertically  at  the  centre  as 
an  axis  to  the  figure,  then  by  dropping  dry  sand,  fine,  coarse, 
and  angular,  in  successive  trials  over  the  axis,  the  slope  at 
wliicli  the  different  kinds  of  sand  come  to  rest  by  gravity, 
under  resistance  from  friction,  may  be  readily  obtained  and 
compared.  If  enough  wator  is  mixed  with  the  finer  sand  or 
earth  to  make  it  flow  like  thin  mud,  the  angles  of  different- 


14  CHARACTERISTICS   OF   VOLCANOES. 

liovviiig  muds  may  be  obtained.  Such  trials  show  that  an 
angle  of  40°  is  as  great  as  should  occur  with  dry  cinders,  un- 
less the  fragments  are  very  irregular  and  light  ;  tiiat  with 
fine  dry  sand  it  may  be  as  low  as  25°  ;  and  that  an  angle  of 
15°  is  not  too  small  for  a  flowing  mud,  though  steeper  slopes 
may  also  occur. 

Cinder-made  cones  are  usually  between  3fh'  and  4(J"  in 
angle  ;  but  they  vary  in  heiglit,  breadth,  and  slope  on  the  dif- 
ferent sides,  according  to  the  direction  of  the  prevalent 
winds.  Alternations  of  cinder  and  lava  ejections  will  mal^e 
a  cone  of  steeper  slope  than  lava  alone ;  and  this  may  be 
part  of  the  reason  for  the  high  angle  of  slope  of  the  volcanic 
mountains  of  western  America.  Summit  ejections  of  cinders 
may  increase  height  without  adding  much  to  the  mass  of  a 
mountain. 

.Flowing  muds  are  made  out  of  volcanic  ashes  or  cinders 
when  waters  descend  in  torrents  during  copious  violent  pro- 
jectile eruptions.  The  stream  of  mud  so  produced  may  flow 
off  at  a  small  angle  of  pitch,  and  make  a  low-angled,  broad- 
topped  cone,  with  a  broad,  saucer-like  crater,  —  a  tufa-cone. 
If  the  vent  is  at  the  sea-level  or  a  little  below  it,  so  that  the 
sea-water  would  be  made  to  boil  up  by  the  heat  of  the  vent 
and  escape  with  the  projected  cinders  or  ashes,  the  mud- 
stream  would  flow  directly  from  the  interior  of  the  crater. 
Punchbowl,  Diamond  Head,  and  the  hills  of  Koko  Head, 
figured  on  Plate  XIV.,  are  examples  of  tufa-cones. 

By  making  an  outline  of  a  section  of  a  cone  and  drawing 
lines  parallel  to  the  sides,  the  usual  figure  of  a  section  of  a 
lava-cone  or  cinder-cone  is  obtained.  But  as  lava-streams  are 
to  a  large  extent  strips  or  patches  of  lava  over  the  surface, 
the  diagram  conveys  a  wrong  impression,  since  it  seems  to 
imply  that  the  cone  consists  of  a  regular  series  of  coats.  In 
a  tufa-cone  there  is  a  slope  beneath  the  crater,  as  well  as 
down  the  outer  surface,  —  a  structure  illustrated  in  the  left 
of  the  Koko  Head  craters  on  Plate  XIV. 


METHODS  AND   CAUSES  OF   VOLCANIC  ACTION.  15 

Ejections  of  volcanic  cinders  or  ashes  from  the  chief  vent 
or  crater  of  a  basalt-volcano  are  generally  of  small  amount ; 
but  they  may  make  beds  a  thousand  feet  or  more  thick  about 
volcanoes  of  other  kinds. 

NoN- Volcanic  Igneous  Ejections.  —  Ejections  of  melted 
rock  like  those  of  volcanoes,  and  of  great  extent,  have  often 
taken  place  without  volcanic  agency.  Fissures  have  opened 
in  the  earth's  crust  and  let  out  liquid  rock,  sometimes  with 
little  overflow  or  none,  but  sometimes  spreading  over  thou- 
sands of  square  miles.  Occasionally  the  lavas  have  been 
forced  in  between  the  beds  of  rock  of  a  reo;ion  so  as  to 
make  great  intercalated  sheets,  or  have  thickened  up  under 
the  cover  of  other  rocks  into  great  dome-shaped  masses,  over 
a  thousand  feet  thick,  called  by  Prof.  G.  K.  Gilbert  "  lacco- 
lites  "  (laccoliths). 

A  fissure  in  a  case  of  ordinary  non-volcanic  igneous  ejection 
affords  its  single  outflow,  and  thus  differs  from  a  volcanic 
vent.  Fissure  may  succeed  fissure,  however,  and  great 
thickness  of  beds  be  attained  in  the  region  through  the 
successive  discharges.  But  there  could  be  no  pericentric  ar- 
rancrement  of  the  beds,  or  a  hio;her  central  resrion,  unless  the 
Assuring  be  subordinate  to  a  central  vent ;  and  in  this  latter 
<3ase  the  ejections  would  be  distinctively  volcanic.  But  the 
characters  of  the  flows  and  of  the  rocks  are  essentially  the 
same,  whether  from  fissures  about  a  volcano  or  from  those  of 
non-volcanic  regions. 

IV.    METHODS   AND   CAUSES    OP   VOLCANIC   ACTION. 

The  Sup2)lyirig  of  Lava.  —  A  continued  supply  of  lava 
from  depths  below  is  required  for  volcanic  activity,  since  an 
enormous  loss  of  lava  takes  place  at  an  eruption. 

Moreover,  the  supply-channel,  or  conduit  as  it  is  often 
■called,  must  reach  down  to  a  region  of  perpetual  heat  and 


16  CHARACTERISTICS   OF   VOLCANOES. 

fusion.  For  the  liquid  column  loses  heat,  owing  (1)  to  con- 
tact with  the  cool  rocks  alongside  of  it ;  (2)  to  the  expan- 
sion of  vapors  or  vaporizable  material  within  the  lava  (all 
such  expansion  using  up  heat),  which  expansion  becomes  of 
large  amount  near  the  surface,  as  the  superincumbent  pres- 
sure in  the  liquid  becomes  small  ;  and  (.3)  to  contact  at 
surface  with  the  air. 

This  supply  of  liquid  rock  from  a  deep-seated  source  sup- 
poses some  upthrusting  force  or  forces,  sufficient  to  push  the 
lava  up  to  the  level  of  the  bottom  of  the  crater.  If  the 
level  reached  is  much  below  the  earth's  surface,  say  some 
thousands  of  feet,  the  melted  rock  might  be  a  source  of  heat 
for  any  waters  that  may  descend  to  it  from  the  surface  to 
bring  it  up,  and  might  thus  make  hot  springs  or  geysers,  or 
at  a  higher  level  might  produce  a  region  of  escaping  vapors 
called  a  soJfatara. 

For  volcanic  action,  the  ascensive  force,  or  combination  of 
forces,  must  be  sufficient  to  restore  the  lava-column  to  its 
mean  height  sooner  or  later  after  every  eruption  ;  for  failure 
here  is  the  beginning  of  decline  in  volcanic  activity.  When 
a  volcano  ceases  action  entirely,  not  even  vapors  escaping,  it 
is  said  to  be  extinct ;  but  it  may  not  always  be  so  dead  that 
a  century  later  it  will  not  break  out  anew. 

The  Work  inaicU  the  Grater  at  the  Extremity  of  the  Lava- 
column.  —  The  work  done  in  a  crater  is  largely  due  to  the 
expansive  force  of  vapors,  and  directly  to  the  making  and 
escaping  of  vapors.  For  if  all  vaporizable  material  were 
absent,  the  lavas  would  lie  quiet,  and  an  eruption,  if  it  w^ere 
a  possibility,  would  be  simply  a  running  over.  Whenever,  in 
the  bottom  of  a  crater  or  in  any  part  of  it,  liquid  lavas  are 
visible,  they  are  always  found  to  be  in  constant  activity  ;  and 
if  not  actually  in  sight,  there  is  usually  considerable  noisy  ac- 
tion from  the  escaping  steam,  and  from  t  he  movements  below 
which  it  occasions. 

The  escape  of  vapor  encounters  resistance  in  consequence 


METHODS   AND   CAUSES   OF   VOLCANIC   ACTION.  17 

of  the  cohesion  of  the  liquid  material,  which  resistance  is 
proportional  to  the  strength  of  this  cohesion,  or  is  conversely 
as  the  degree  of  liquidity.  Water,  in  boiling,  lets  very  small 
babbles  of  steam  through  easily  ;  and  the  elastic  force  of  the 
steam  of  the  bubble  makes  low  jets,  the  height  only  one  or 
two  inches.  But  to  overcome  the  resistance  in  lava  and 
break  a  way  through,  the  elastic  force  of  a  small  bubble  of 
vapor  is  too  feeble  ;  the  bubble,  tlierefore,  keeps  enlarging 
by  additions  until  the  force  is  sufficient  to  overbalance  the 
resistance ;  and  then  comes  the  break  of  the  liquid  lava-shell 
of  the  bubble,  and  the  projection  of  its  fragments  verti- 
cally or  nearly  so  into  the  air,  —  vertically,  because  the  shell 
is  thinnest  at  top.  The  projectile  force  thus  depends  (1) 
largely  on  the  size  of  the  Imbljle,  or,  what  is  the  same  thing, 
on  the  viscidity  of  the  liquid  lava  ;  and  also  on  the  supply 
of  vapors  seeking  to  escape. 

On  account  of  the  remarkable  liquidity  of  basaltic  lavas, 
the  projectile  force  required  to  break  a  way  through  may  be 
so  small  as  to  throw  the  lava  to  a  height  of  only  a  few  yards, 
as  in  Kilauea, — a  height  so  small  that  the  projected  drops 
or  masses  of  lava  fall  back  unsolidified,  and  the  jets  dance  in 
a  lively  and  brilliant  way  over  the  surface  of  the  lava-basin, 
like  those  over  a  boiling  vat.  Where  the  surface  of  liquid 
lava  is  small,  as  in  half-covered  oven-like  places  about  the 
sides  of  a  basin,  the  escape  of  the  vapors  produces  a  throw  oi 
fiery  spray. 

Again  :  where  such  lavas  are  jetted  out  of  small  apertures, 
the  driblets  fall  back  upon  one  another,  and,  becoming  sol- 
dered together,  make  fantastic  driblet-cones.  (Figures  are 
given  on  pages  71,  85.)  The  projecting  steam,  in  such 
cases,  often  escapes  from  the  aperture  with  a  rush  like 
that  from  a  steam-engine ;  hence  the  terms  hloiv-hole  and 
bloivi?ig-cone. 

But  when  the  liquid  lavas  are  of  the  stiffer  sort,  the  bubbles 
have  to  become  large  before  escape  of  the  vapor  is  possible : 


18  CHARACTERISTICS  OF  VOLCANOES. 

and  then,  on  breaking,  the  explosive  force  projects  the  frag- 
ments of  the  hiva-shell  to  a  height  of  hundreds  or  thousands 
of  feet.  The  projected  fragments,  cooled  in  their  flight,  are 
the  volcanic  sand  or  dust,  cinders  or  lapilli,  which,  in  falling, 
make  the  cinder-cone  about  the  vent,  or  cover  slopes  or  the 
country  about  the  volcanic  mountain  with  thick  deposits  of 
loose  volcanic  ashes  or  scoria. 

Such  high  projections  have  occurred  under  rare  conditions 
in  connection  with  the  Hawaiian  volcanoes.  They  are  the 
common  fact  at  most  volcanoes ;  and  it  is  well  known  that 
in  some  eruptions  they  reach  a  height  of  ten  thousand  feet 
and  beyond.  Great  viscidity,  while  leading  to  the  production 
of  large  size  in  the  vapor-made  bubbles  before  they  are  ready 
for  explosion,  makes  fewer  of  them  to  form  over  a  given  sur- 
face of  liquid  lava ;  and  in  times  of  moderate  activity  the 
number  may  be  only  half  a  dozen  or  only  a  single  one  at  a 
time,  while  on  a  like  area  lavas  with  the  Kilauea  degree  of 
viscidity  would  have  scores  or  hundreds.  When  the  author 
was  at  Naples,  in  May  of  1834,  there  was  at  night  an  interval 
of  seven  to  eight  minutes  between  the  explosions,  or  the 
throw  (some  hundreds  of  feet  in  height)  of  fiery  cinders;  on 
the  ascent,  the  following  day,  the  interval  was  four  to  five 
minutes ;  and  on  passing  Stromboli,  a  fortnight  later,  June 
16,  it  was  fifteen  to  twenty  minutes,  —  the  activity  being- 
less  than  usual;  explosions  every  two  or  three  minutes  being 
common.  As  Spallanzani,  Hofmann,  and  others  have  seen 
the  rising  bubble  within  Stromboli,  the  bursting,  and,  follow- 
ing this,  the  rush  of  vapor  and  the  cinder  projections,  there 
is  no  reason  to  doubt  that  at  Vesuvius,  also,  each  throw  of 
cinders  has  the  same  source.  Mr.  John  Milne  states  that  on 
his  ascent  of  the  Japan  volcano,  Oshima.  in  May,  1877,  on 
approaching  the  top,  successive  explosions  were  heard  every 
two  seconds  with  occasional  pauses,  which  explosions  he 
found,  on  reaching  the  top,  to  be  due  to  successive  outbursts 
of    steam,  each    projecting   ashes  and    lava-fragments    to    a 


METHODS   AND    CAUSES   OF   VOLCANIC    ACTION.  19 

height  of  nearly  six  thousand  feet,  that  fell  vertically  unless 
wafted  by  the  winds. ^ 

When  the  rains  descend  in  torrents  at  a  great  eruption, 
these  materials  make  the  flowing  mud  that  buries  fields  and 
forests,  and  has  made  fossils  of  cities,  of  which  Herculaneum 
and  Pompeii  are  examples. 

The  vapor  of  water,  as  has  been  stated,  is  the  chief  part  of 
the  vapors  expelled.  Above  the  surface  of  liquid  lava,  from 
which  it  escapes,  it  is  for  some  distance  invisible,  because  the 
temperature  of  the  liquid  lava  is  near  2000°  F.  It  becomes 
clouds  by  condensation  at  whatever  height  the  required  tem- 
perature is  reached. 

For  the  supply  of  water,  the  sea  may  be  a  source ;  and  so 
also  the  rains,  whence  come  not  only  the  streams  of  the  sur- 
face but  also  subterranean  streams.  The  waters  may  descend 
deeply  into  the  cavernous  volcanic  mountain.  Approaching 
the  hot  rocks  about  the  lava  column,  they  would  be  thrown 
into  steam,  —  a  cubic  foot  of  steam,  if  under  the  ordinary 
atmospheric  pressure,  to  every  cubic  inch  of  water.  So  vast 
is  the  amount  of  vapor  that  would  thus  come  from  a  small 
amount  of  water,  that  the  vapor,  unable  to  escape  through 
the  rocks,  would  be  forced  into  the  rising  lavas  of  the  con- 
duit. Moreover,  a  molecular  absorption  of  vapor  of  water 
against  the  pressure  within  has  been  shown  by  Daubree  to 
take  place. 

Another  source  of  water-vapor  recognized  among  writers 
on  volcanoes  is  the  deep  subterranean  region  which  supplies 
the  lavas.  Further,  if  the  fusion  has  been  produced  by 
the  melting,  through  earth-movements  or  otherwise,  of  pre- 
existing rocks,  the  moisture  of  these  rocks  (perhaps  half  per 
cent  of  their  weight)  would  be  a  source  of  rising  vapors. 

Other  effects  of  the  vapors  are  these:  (1)  They  enlarge, 
by  their  expansion,  the  bulk  of  the  liquid  lava,  and  may  thus 

1  Milne,  "Volcanoes  of  Japan,"  Transactions  of  the  Seismological  Society  of 
Japan,  1886,  vol.  ix.  part  ii. 


20  CHARACTERISTICS   OF   VOLCANOES. 

increase  the  height  of  the  lava-coliimn.  (2)  They  make  vesi- 
cles or  air-cells  in  the  lava.  (3)  They  produce  fractures  in 
the  walls  of  craters  or  in  the  sides  of  the  volcanic  mountain 
by  the  sudden  generation  or  slower  accumulation  of  large 
quantities  within  regions  about  or  beneath  the  crater.  (4) 
They  may  produce  violent  projectile  effects  when  water  in 
large  quantity  gains  direct  access  to  the  lava-conduit.  (5) 
They  bring  pressure  to  bear  on  surfaces  of  liquid  lava  be- 
neath, and  often  force  the  lava  into  opened  fissures  and 
up  to  levels  hundreds  of  feet  above  the  bottom  of  the  cra- 
ter, acting  here  on  the  principle  exemplified  in  a  Pennsyl- 
vania oil-well. 

Progress  toward  an  Eruption.  —  The  crater,  after  it  has 
been  emptied  by  a  great  discharge  at  a  time  of  eruption, 
often  has,  at  first,  a  period  of  apparently  extinguished  fires, 
and  something  like  the  conditions  of  a  commencing  solfatara, 
through  the  lazy  escape  of  vapors  from  the  fissures  and  the 
lining  of  fissures  with  sulphur  crystals.  Next,  little  outflows 
of  lava  take  place  from  apertures  or  fissures  in  some  part  of 
the  bottom  or  floor  of  the  crater,  or  driblets  of  lava  or  jets 
of  cinders  build  a  small  cone  about  a  vent.  In  the  case  of 
basaltic  lavas,  pools  of  boiling  lava  often  appear  in  the 
crater,  which  frequently  overflow  and  spread  lava-streams 
over  the  floor,  making  thus  small  eruptions.  In  the  case 
of  the  less  liquid  lavas  the  ejections  at  the  bottom  of  the 
crater  are  mostly  of  cinders,  and  one  or  more  cinder-cones 
are  made  thereby  over  the  bottom ;  but  now  and  then  es- 
capes of  lava  take  place  through  fissures.  The  process  is 
one  that  puts  new  material  over  the  bottom  of  the  crater 
and  raises  its  level  ;  and  it  goes  on  at  an  increasing  rate 
until  the  eruption  commences. 

But  this  raising  of  the  bottom  by  overflows  and  deposits  of 
cinders  is  accompanied  by  the  upward  thrust  of  the  lavas  of 
the  lava-column  through  the  ascensive  action  already  men- 
tioned.    Owing  to  this   ascensive  action,  aided  by  the  ejec- 


METHODS   AND   CAUSES   OF   VOLCANIC   ACTION.  21 

tious,  the  floor  of  the  crater  keeps  rising ;  and  sometimes, 
perhaps  generally,  the  larger  part  of  the  floor  is  lifted  or 
shoved  up  bodily  by  the  lavas  forced  in  beneath. 

By  these  methods  the  level  of  the  floor  in  a  volcano  like 
Vesuvius  may  rise  nearly  to  the  very  brink  of  the  crater ; 
or,  in  one  like  Kilauea,  at  least  some  hundreds  of  feet. 
At  such  times  the  projectile  action  of  the  crater  has  be- 
come intense.  Clouds  rising  in  great  volumes  over  the 
mountain  are  evidence  of  the  activity,  and  an  illuminated 
signal  at  night. 

The  Eruption.  —  The  eruption  begins  when  the  pressure 
from  the  vapors  generated  and  confined  below  and  from 
the  hydrostatic  pressure  of  the  lava-column  —  chiefly  the 
former  —  is  too  great  to  be  withstood  by  the  containing 
mountain.  The  mountain  therefore  breaks,  the  conduit  is 
rent  open  on  one  side  or  the  other,  and  the  lavas  run  out. 
If  the  mountain  is  too  strong  to  break,  as  it  perhaps  is  in 
the  earlier  part  of  its  history  when  it  is  of  little  height, 
the  lava  would  rise  to  the  top  of  the  crater  by  the  methods 
stated,  and  overflow  on  this  side  or  that ;  and  thus  the 
lava-flood  would  begin  at  the  summit.  But  eruptions  at 
the  present  day,  as  has  been  stated,  are  usually  through 
fissures. 

The  discharge  of  tJie  lavas  (1)  empties  the  upper  part  of 
the  lava-conduit  or  lowers  the  level  of  its  upper  surface,  and 
(2)  undermines  the  lifted  crater-floor ;  and  the  result  may 
be  (3)  a  collapse  or  down-plunge  within  the  crater,  making 
it  again  hundreds  of  feet  deep,  or  a  thousand,  or  two  thou- 
sand, as  the  case  may  be. 

Part  of  the  undermining  at  Vesuvius  is  due  to  outflow  of 
lavas,  part  to  discharge  of  volcanic  cinders ;  but  at  Kilauea 
it  all  comes,  ordinarily,  from  the  escape  of  liquid  lavas. 

The  collapse  from  the  loss  of  lavas  may  be  followed  by  a 
general  chilling  of  the  rocks  down  to  the  new  lava-surface, 
and  a  long  period  of  quiet.     Before  tlie  mountain  is  ready 


22  CHAKACTEKISTICS   UF   VOLCANOES. 

for  another  eruption  the  process  of  filling  up  again,  b\'  tlie 
methods  described,  has  to  be  repeated,  and  this  may  take 
many  years.  An  empty  caldron  will  not  overflow  before  its 
cracks  are  mended  and  the  steam-apparatus  at  work  has 
again  filled  it ;  and  it  might  be  so  badly  cracked,  and  the 
supply  of  heat  so  cut  off,  as  to  fail  of  further  use.  Should 
the  ascensive  force  for  any  cause  cease  to  work,  death 
would  be  sure. 

Earthquakes^  in  connection  loith  Volcanic  Eruptio/is.  — 
When  the  breaking  of  the  mountain  is  caused  by  vapors 
suddenly  produced  in  large  volume,  and  the  resistance  to 
fracture  is  very  great  for  any  reason,  the  vibrations  attend- 
ing the  rending  may  be  vigorous,  opening  deep  fissures,  over- 
turning houses,  and  making  underground  rumblings.  But 
in  other  cases  the  vibrations  may  be  imperceptible,  as  is 
usually  the  fact  both  in  Kilauea  and  Mount  Loa  at  their 
greatest  eruptions. 

SuborxUnate  or  Lateral  Volcanic  Cones.  —  Lateral  volcanic 
cones  are  described,  on  page  3,  as  sometimes  forming  over 
fissures.  Each  such  cone  when  it  is  in  progress  has  its  own 
lava-column,  as  a  branch  from  the  general  lava-column  of 
the  mountain.  But  it  is  relatively  small,  and  the  liquid 
lavas  consequently  may  soon  become  chilled  by  the  cold 
rocks  about  it ;  and  hence  such  lateral  or  subordinate  vol- 
canoes have  usually  only  a  brief  existence.  They,  however, 
often  work  hard  while  the  time  lasts,  and  even  in  two  or 
three  weeks  may  make  a  cone  many  hundred  feet  or  yards 
in  height.  They  occur  about  the  sources  of  great  eruptions. 
But  they  are  most  common  near  the  seashore,  where  subter- 
ranean fresh  waters  most  abound  for  the  supply  of  moisture, 
and  where  the  sea  is  at  hand  as  another  source.  The  vol- 
canic origin  of  such  cinder-cones  can  be  proved,  if  a  fact, 
by  the  pericentric  arrangement  of  the  materials  constituting 
them.  The  sea.  with  its  broad  waves  and  the  aiding  winds, 
can  make  heaps  or  ridges   out  of  the   sands  existing  or  pro- 


METHODS   AND   CAUSES   OF   VOLCANIC   ACTION.  23 

duced  on  its  borders,  but  it  cannot  arrange  the  layers  of  sand 
or  earth  pericentrically  into  a  conical  hill. 

Explosive  Eruptions.  —  When  water  in  large  volumes  gains 
sudden  access  to  the  interior  of  a  lava-conduit,  —  that  is,  to 
the  liquid  lavas  of  the  lava-column,  — the  projectile  force  of 
the  aljruptly  generated  vapors  may  be  enormous,  and  produce 
projectile  discharges  of  lava  of  terrific  violence,  covering  a 
wide  reach  of  country  with  volcanic  cinders  and  ashes.  More- 
over, great  masses  of  solid  lava  may  be  torn  off  in  such  cases 
from  the  throat  of  the  volcano,  and  add  to  the  projections. 
Masses  of  a  hundred  cubic  feet  and  more  may  be  hurled  for 
miles  from  the  scene  of  explosion.  Such  an  eruption  is  very 
unlike  the  ordinary  kind  described  above.  It  is  an  exj^losive 
eruption.  In  some  of  the  most  violent  of  explosive  eruptions 
no  outflow  of  lava  takes  place.  The  projectile  eruption  is  all, 
and  this  is  soon  ended.  Some  examples  of  such  eruptions 
are  described  on  a  following  page. 

Explosive  eruptions  of  another  kind,  which  might  be  styled 
semi-volcanic,  are  included  among  descril3ed  volcanic  phe- 
nomena. In  such  eruptions  water  in  large  volumes  gains 
sudden  access  to  the  heated  depths  beneath  an  extinct  or 
feebly  active  volcanic  mountain  through  fractures  or  move- 
ments along  planes  of  weakness,  as  in  other  cases  ;  but  the 
heated  depths  are  depths  sliort  of  the  2000°  F.  or  over  re- 
quired for  fusion.  The  consequences  are  earth-shakings,  ex- 
plosions from  the  suddenly  generated  steam,  the  rending  of 
rocks  in  the  deep-seated  region  of  the  explosions,  projectile 
action  throwino;  the  stones  and  o;reat  rock-masses  so  made 
and  the  dust  from  abrasion  into  the  air  and  over  the  adjoin- 
ing region,  attended  by  vast  and  violent  effusions  of  steam, 
making  darkness  and  terrific  storms  about  the  mountain,  — 
and  not  outflows  of  lava  nor  the  projection  of  volcanic  ashes 
and  scoria  from  cooled  lavas.  No  liquid  lavas  are  in  any  way 
directly  concerned,  and  hence  the  eruptions  are  only  semi- 
volcanic.    They  may  get  over  their  violence  in  an  hour  or  less. 


24  CHAKACTERISTICS   OF   VOLCANOES. 

Such  projections  make  great  cavities  beneath,  undermining 
the  mountain ;  and  a  down-plunge  or  subsidence  of  the  moun- 
tain summit  to  hll  the  cavities  should  be  a  consequence. 
Since  force  acts  most  violently  where  the  generator  of  the 
steam  exists,  as  in  other  explosive  eruptions,  and  compara- 
tively feebly  after  the  vapors  have  made  their  escape  into  the 
open  air,  the  chief  destruction  to  the  mountain  cannot  come 
from  any  blowing  of  steam,  or  air,  or  projection  of  rocks, 
against  the  outside  walls  or  peaks. 

The  origin  of  volcanic  heat,  the  source  of  lava-eolimins 
beneath  the  volcano,  the  cause  of  the  ascensive  force  in  the 
lava- column  are  subjects  on  which  science  has  various  opin- 
ions and  no  positive  knowledge. 


part  ^cconD* 

CONTRIBUTIONS    FROM    THE    HAWAIIAN    ISLANDS 
TO   THE   SCIENCE   OF    VOLCANOES. 

1'^HE  Hawaiian  Island  group  is  an  example  of  a  line  of 
g-reat  volcanic  mountains.  Fifteen  volcanoes  of  the 
first  class  have  existed,  and  have  been  in  brilliant  action 
alonsji:  the  line.  All  but  three  are  now  extinct  ;  and  these 
three  are  on  the  easternmost  and  largest  island  of  the 
group,  —  Hawaii.  Hawaii  is  made  up  of  five  of  the  vol- 
canic mountains,  —  Kea,  13,805  feet  in  height;  Loa,  13,675 
feet ;  Hualalai,  8,273  feet ;  Kilauea,  4,040  feet  at  the  Vol- 
cano House,  but  4,158  feet  at  the  highest  point  on  the  west 
side  ;  and  Kohala,  5,505  feet.  But  they  have  encroached 
much  on  one  another  by  their  eruptions  ;  and  Kohala,  the 
oldest  and  most  northern,  is  largely  buried  by  the  lava 
of   Kea. 

The  island  of  Maui  is  a  volcanic  doublet.  The  eastern 
mountain  of  Maui  —  Haleakala,  10,032  feet  high  —  looks  as 
fresh  in  its  lavas  and  as  smooth  in  its  slopes  as  a  volcano 
still  in  activity.  But  the  other  mountain  —  that  of  western 
Maui  or  Eeka  —  has  lost  by  long  denudation  its  summit 
crater,  its  old  even  slopes,  and  a  large  part  of  the  old 
cone. 

Oahu  is  another  volcanic  doublet ;  and  both  its  eastern  and 
western  mountains  have,  like  Mount  Eeka,  lost  the  crater 
that  was  the  great  centre  of  action  ;  and  besides  they  have 
lost  much    also  by  catastrophes   of   a  subterranean   source. 


26 


VOLCANIC  PHENOMENA 


Still  the  lava-streams  of  the  old  cones  may  be  made  out  on 
each,  and  in  one  perhaps  the  site  of  the  ancient  crater. 

Molokai  is  another  volcanic  doublet ;  and  probably  also 
Kauai,  although  the  larger  part  of  the  present  island  appears 
to  belong  to  one  great  cone  or  dome. 


OF   THE  HAWAIIAN  ISLANDS.  27 

The  group  appears,  in  fact,  to  be  a  double  line  of  volcanoes 
from  Oahu  eastward.  One  line,  the  northern,  called  the 
"  Kea  Range "  from  Mount  Kea  of  Hawaii,  includes  the 
northeastern  mountain  of  Oahu,  Molokai,  the  two  mountains 
of  Maui,  and  Kohala  and  Kea  on  Hawaii ;  tlie  other,  the 
''  Loa  Range,"  includes  the  southwestern  mountain  of  Oahu, 
Lanai,  Kahoolawe,  and  the  volcanoes  of  Hualalai  and  Loa 
on  Hawaii. 

The  island  Niihau,  at  the  west  end  of  the  group,  southwest 
of  Kauai,  has  a  position  transverse  to  that  of  the  general 
trend  of  the  islands. 

The  depth  of  ocean  about  the  islands,  so  far  as  soundings 
have  been  made,  varies  from  2,000  to  3,02o  fathoms,  as  is 
shown  on  the  map  ;  and  as  the  cones  stand  on  the  sea- 
bottom,  the  whole  heio-ht  of  the  liioher  mountains  of  Hawaii 
above  the  base  to  the  eastward  is  not  far  from  31,000 
feet. 

The  Hawaiian  group  is  an  example  of  the  lines  of  vol- 
canoes that  characterize  many  island  ranges  over  the  globe 
and  volcanic  ranges  over  the  continents. 

The  volcanic  features  and  phenomena  of  the  Hawaiian 
Islands  are  described  and  discussed  in  the  following  pages 
from  personal  observations  in  1840  and  1887,  from  the  vari- 
ous records  of  others,  and  from  the  topographic  surveys  of 
the  islands  made  under  the  direction  of  Prof.  W.  D.  Alex- 
ander, Surveyor-General  of  the  Hawaiian  Islands. 

As  the  island  of  Hawaii  is  the  held  of  existing  volcanic 
fires,  and  therefore  of  greatest  interest,  the  facts  relating  to 
it  and  the  views  on  volcanic  action  thence  deduced  come  first 
under  consideration,  after  general  remarks  on  the  group, 
and  then  the  results  of  observations  on  the  other  islands,  and 
the  relations  of  the  group  to  the  system  of  islands  in  the 
Pacific  Ocean. 


ii8  VOLCANIC   PHENOMENA. 


I.    THE    ISLAND    OF   HA  WAIL 

General  Observations.  —  A  map  of  Hawaii  makes  the 
frontispiece  to  the  volume.  The  island  is  approximately 
triangular,  with  its  greatest  length  from  nortli  to  south 
about  ninety-three  miles,  and  the  extreme  width  eighty  miles. 
It  lies  mostly  between  the  parallels  of  19°  and  20°  20',  and 
takes  the  trades  on  its  northeast  side. 

Many  important  facts  may  be  read  from  the  map  at  a 
glance.  Among  them  the  first  to  be  noted  is  the  simplicity 
of  the  topography  and  the  gentleness  of  the  mountain  slopes ; 
secondly,  the  situation  of  the  five  volcanic  mountains ; 
thirdly,  the  almost  total  absence  of  rivers,  except  on  the 
north  and  northeast  slopes,  or  the  windward  sides ;  and 
fourthly,  the  courses  of  the  great  lava-streams  of  the  past 
sixty  years,  indicated  by  long  dotted  areas. 

The  Kohala  Range,  on  the  nortli,  is  the  remains  of  the 
oldest  of  the  Hawaiian  volcanoes.  The  slopes  are  deeply  cut 
by  valleys  of  denudation.  Between  it  and  Mount  Kea  lie  the 
broad  plains  of  Waimea,  2.500  to  3,000  feet  above  tide-level, 
made  by  the  lavas  of  the  base  of  Mount  Kea.  On  the  north- 
eastward, the  ocean  side,  there  are  the  precipitous  gorges  of 
Waipio  and  Waimanu,  1,000  to  2,500  feet  in  depth,  so  pro- 
found and  so  bent  around  into  parallelism  with  the  coast 
that  erosion  cannot  explain  their  origin. 

]\Iount  Kea  has  long  been  extinct,  probably  for  centuries, 
yet  not  long  enough  for  denuding  action  from  the  abundant 
rains  over  the  windward  slopes  to  extend  the  torrent  chan- 
nels more  than  half-way  to  the  summit.  Mount  Hualalai 
has  been  quiet  since  1801,  when  the  last  eruption  was  wit- 
nessed by  Turnbull.  It  is  a  question  whether  it  did  not  reach 
final  extinction  as  a  consequence  of  that  discharge.  Its 
slopes  so  blend  with  those  of  Mount  Loa  that  "  it  is  hard  to 
tell    where   one   beorins   and    the   other   ends."      Mount   Loa 


THE   ISLAND   OF   HAWAII.  29 

blends  in  like  manner  with  Mount  Kea,  but  with  a  broader 
intervening  plateau,  about  five  thousand  feet  in  elevation. 
The  great  Dome  of  Mount  Loa  ^  would  have  been  the 
highest  of  the  mountains,  were  it  not  for  the  last  cinder- 
eruptions  of  Mount  Kea,  which  ran  up  a  cinder-cone  to  a 
height  of  one  hundred  and  forty  feet  above  it. 

Kilauea  is  twenty  miles  south  of  west  from  the  crater  of 
Mount  Loa ;  and  although  containing  the  largest  crater  of  the 
group,  the  highest  point  is  raised  hardly  three  hundred  feet 
above  the  plain  between  it  and  Mount  Loa,  and  within  two 
miles  in  that  direction  the  Kilauea  slope  ends.  In  the  op- 
posite direction  Kilauea  may  claim  the  slopes  to  the  shores, 
from  Haena,  southeast  of  Hilo,  to  the  middle  of  the  south 
coast  within   ten   miles  of  Punaluu. 

Hawaii  has  no  fringing  reefs;  only  small  patches  occur 
here  and  there  along  the  shores.  The  fact  is  a  consequence 
of  the  destruction  of  life  from  submarine  eruptions,  and  the 
encroachment  also  of  subaerial  lava-floods.  It  has  therefore 
no  first-rate  harbor.  That  of  Ililo  is  the  best ;  and  the  vil- 
lage of  Hilo  is  consequently  the  chief  settlement.  The 
longest  of  Hawaiian  rivers,  the  Wailuku,  which  follows  in 
its  lower  part  the  meeting  of  the  slopes  of  Kea  and  Loa, 
here  enters  the  sea,  and  adds  much  to  the  capabilities  and 
the  beauties  of  the  surrounding  region.  At  the  Pei-pei  Falls 
above  Hilo,  it  flows  between  high  l)luffs  of  basaltic  columns. 

Hilo  is  the  usual  starting-point  for  excursions  to  Kilauea. 
The  old  saddle-road  is  indicated  on  the  map  by  a  dotted  line. 
The  distance  is  about  thirty  miles.  174^  miles  of  it  beyond  the 
''  Half-way  House."  The  new  carriage-road,  which  follows 
nearly  the  same  course,  has  reduced  the  time  of  the  jour- 
ney, and  added  much  to  its  pleasures.  Another  and  a 
much  shorter  route  is  from  Keauhou,  on  the  southern  coast. 
It  makes  the  whole  ascent  of  4,000  feet  in  about  ten  miles' 
direct  distance,  or  twelve  miles  by  the  road,  rising  852  feet  in 

^  The  words  "  Mauiia  Loa  "  mean  "  Loiiir  Mountain." 


30  VOLCANIC    PHENOxMENA. 

the  first  mile,  and  between  the  third  and  fifth  miles  (as  the 
road  goes)  about  700  feet,  which  carries  the  road  to  the 
summit  of  the  ''  pali,"  or  a  long  precipice  that  here  extends 
along  for  more  than  twenty  miles  parallel  nearly  with  the 
coast.^  A  third  route  to  Kilauea,  and  one  of  much  interest, 
starts  from  Punaluu,  on  the  southern  coast,  where  there  is  a 
good  hotel.  The  steamer  to  and  from  Punaluu  passes  around 
the  southern  cape,  and  affords  a  chance  for  a  distant  view  of 
the  lava-streams  of  1868  and  1887,  at  the  commencement  of 
whose  discharge  earthquakes  shook  the  whole  island,  and 
the  southern  half  of  it  disastrously. 

Kealakekua,  on  the  west  coast,  is  the  place  where  Captain 
Cook  was  killed  by  the  natives  in  1779.  It  is  an  interesting 
place  geologically  on  account  of  the  lofty  cliffs  that  here 
face  the  sea,  — evidence  apparently  of  great  fracturing  and 
subsidence. 

The  slopes  of  Mount  Loa  are  under  forests  up  to  from 
seven  to  eight  thousand  feet  on  the  north  and  east  sides, 
and  over  much  of  the  southeast  to  a  line  drawn  from 
the  summit  through  Kilauea,  —  the  limit  of  the  region 
struck  by  the  trade-winds.  The  rest  of  the  surface,  with 
part  also  of  the  forest  portion,  is  a  nearly  bare  surface  of 
lava-streams,  either  the  pahoehoe  or  aa,  with  little  shrub- 
bery. The  fields  of  aa  are  the  chief  ol^stacle  in  an  ascent 
to  the  summit  outside  of  the  usual  track.  As  the  jagged 
masses  are  from  one  cubic  foot  to  ten  thousand  in  size,  and 
touch  only  by  their  points  and  edges,  leaving  deep  recesses 
everywhere  among  them,  any  crossing  on  horseback,  except 
by  a  made  road,  is  impossible  ;  and   the   pedestrian   has  to 

1  The  road  was  made  by  the  Wilder  Steamship  Company,  and  they  publish  the 
following  as  the  levels  of  the  road  at  each  mile-stone  along  it,  starting  from  Keauhou  : 
1st,  852  feet;  2d,  1,113  ;  3d,  1,841 ;  4th,  2,287  ;  5th,  2,504 ;  6th,  2,867  ;  7th,  3,204; 
8th,  3,341;  9th,  3,395;  10th,  .3,629;  llth,  3,748;  12th,  4,008  ;  13th,  3,964  ;] 4th, 
4,040,  Volcano  House.  The  Keauhou  Eanch,  a  half-way  house,  is  six  miles  from 
Keauhou  Landing  ;  at  nine  miles  the  road  sends  off  a  branch  to  the  southeast- 
ward to  Puna.  The  Volcano  House  is  under  the  direction  of  the  Steamship 
Compnny. 


THE    ISLAND   OF   HAWAU.  31 

look  to  it  that  he  does  not  miss  his  footing  and  break  his 
limbs  in  a  fall  among  the  jagged  masses.  Moreover,  some 
aa  fields  are  so  large  that  when  upon  them  all  in  sight  to  the 
horizon  around  is  gray  and  black  desolation.  The  author 
made  his  first  acquaintance  with  the  two  styles  of  lava-fields 
in  1840  on  his  walk  from  Kaulanamauna,  on  the  southwest 
coast,  to  Waiohinu,  Honuapo,  Punaluu,  and  Kilauea. 

The  pahoehoe  also  is  exceedingly  uneven,  through  its 
many  rounded  hillocks  or  domes  (half  of  which  are  caved 
in),  its  ropy  ridges,  and  its  knobs  and  mouldings  made  by 
the  extrusion  of  flowing  lavas  through  the  hardened  crust  of 
a  stream ;  but  travelling  over  it  is  safe,  and  a  mule  will  avoid 
the  holes  and  crevices. 

The  General  Charactee  of  the  Great  Craters  and 
OF  the  Facts  they  afford.  —  The  active  craters  of  the 
island  —  Kilauea,  and  Mokuaweoweo  or  the  Mount  Loa 
crater  —  are  alike  in  being  int-craters,  or  cratei's  with  mostly 
vertical  walls  without  an  enclosino;  cone  above  the  walls ; 
and  these  walls  are  made  of  the  nearly  horizontal  edges  of 
stratified  lava-streams. 

A  sketch  of  Kilauea,  as  it  appeared  in  December,  1840,  by 
Drayton,  one  of  the  two  artists  of  the  Wilkes  Exploring  Ex- 
pedition, is  reproduced  in  Plate  II.  from  the  "  Narrative  of 
Captain  Wilkes."  ^  A  knowledge  of  the  features  of  the  pit 
at  that  time  is  necessary  to  enable  the  reader  to  understand 
the  history  beyond.     It  was   taken  from  the  west  angle  of 

^  Copied  from  the  plate  facing  page  125  in  the  fourth  volume  of  Wilkes's  "  Nar- 
rative." One  or  two  points  of  geological  importance  were  overlooked  by  the  artist, 
which  should  be  mentioned  to  forestall  wrong  inferences  :  One  is  the  omission  of 
the  stratification  of  the  wall,  which  is  a  marked  feature  ;  and  another  is  the  giving 
a  slight  concavity  to  the  floor  of  the  crater  in  the  northern  or  near  part,  which  was 
not  a  fact.  The  small  jets  of  vapor  over  the  bottom  arose  at  the  time,  with  a  single 
exception,  from  fissures  or  cavern-like  openings;  and  such  escapes  of  vapor  are 
greatly  multiplied  by  a  rain.  The  exception  was  that  of  a  lava-lake,  about  two 
hundred  feet  in  diameter,  named  Judd's  Lake  in  the  "Narrative,"  which  was  the 
larger  of  two  lakes  tliat  were  active  two  months  before,  in  November,  1840,  at  tlie 
time  of  the  author's  visit  to  the  crater. 


o2  VOLCANIC    PHENOMENA. 

the  depression  at  the  north  end  of  the  crater,  and  shows  ad- 
mirably the  condition  of  tlie  pit.  Its  length  then  was  four- 
teen thousand  feet,  as  now  ;  but  its  depth  to  the  bottom  of  the 
lower  pit  was  one  thousand  feet.  The  broad,  level  platform 
between  the  lower  pit  and  the  upper  wall,  about  six  hundred 
feet  below  the  top  of  ihe  wall,  is  w4iat  was  then  called  the 
''  Black  Ledge."  At  the  present  time,  as  shown  on  Plate  III., 
there  is  no  lower  pit  and  no  Black  Ledge ;  all  is  filled  up  to 
a  higher  level  than  that  of  the  ledge,  so  that  the  greatest 
depth  below  the  Volcano  House  is  now  but  482  feet,  and  the 
least  about  the  centre  of  the  pit  is  less  than  four  hundred 
feet. 

The  most  active  fires  in  1840  were  in  the  southwest  part 
of  the  crater,  as  has  been  the  fact  through  all  the  known 
history  of  Kilauea.  The  pit  represented  in  the  sketch  to  the 
left  is  the  small  crater  of  Keanakakoi,  which  is  well  shown 
in  Plate  III. 

The  history  of  these  volcanoes  is  such  as  has  been  sup- 
plied by  no  other  volcanic  region.  Commonly  it  is  the  erup- 
tion that  draws  attention  to  the  volcano  ;  and  the  course  of 
the  flow,  the  characteristics  of  the  lava,  and  the  devastations 
of  the  fiery  stream  and  the  earthquakes  make  up  nine  tenths 
of  all  the  published  facts.  At  Kilauea,  on  the  contrary,  it  is 
a  history  of  the  iimer  ivorkings  of  the  volcano  ;  of  the  move- 
ments and  changes  that  take  place  within  the  crater  over 
the  various  parts  of  the  great  area,  where  come  into  view  the 
outlets  of  the  subterranean  lava-column  ;  and  of  these  events 
as  steps  in  the  line  of  progress  from  its  emptied  condition 
after  a  great  eruption   till  ready  again  for  an  outbreak. 

In  Vesuvius  the  crater  may  be  accessible  for  a  time  after 
a  discharge  ;  and  Scacchi  has  done  excellent  work  on  such 
occasions.  But  in  general,  long  before  the  time  of  eruption, 
the  vapors  and  cinder  ejections  make  access  to  the  bottom 
impossible.     The   crater  of   ^tna  is  far  away  from   habita- 


o 

B 

V 


THE    ISLAND  OF    HAWAII.  35 

tions,  and  it  has  therefore  had  no  regidar  series  of  interior 
investigations.  Kilauea  alone  is  always  accessible.  Although 
the  crater  is  so  large,  the  height  is  no  greater  than  that  of 
Vesuvius.  Even  when  ready  for  an  eruption  it  is  safe  to 
stand  on  the  brink  of  the  great  pit  and  watch  the  boiling 
caldrons,  and  sweeping  lava-floods,  and  violent  but  harmless 
blowing-cones.  The  action  of  the  liquid  lavas  is  ordinarily 
so  quiet  and  regular  that  all  parts  of  the  great  open  arena 
may  be  traversed  with  safety  ;  and  the  margins  of  the  fiery 
lakes,  if  the  heat  is  not  too  great,  may  be  made  a  sleeping- 
place  for  the  night,  —  with  only  this  possibility,  that  the 
lavas  may  well  up  and  spill  over.  This  spilling  over  may 
be  the  sending  away  of  a  stream  for  a  mile  or  two  across  the 
crater's  bottom  ;  but  standing  a  little  to  one  side  it  does  no 
damage,  and  the  next  day  the  fresh  lavas  may  be  walked 
upon.  Thus  the  crater  may  be  followed  in  all  its  interior 
changes  month  after  month.  There  is  terrible  sublimity  in 
the  quiet  work  of  the  mighty  forces,  and  also  something 
alluring  in  the  free  ticket  offered  to  all  comers. 

The  records  of  such  a  region,  whoever  the  reporter,  are  of 
great  importance  to  science ;  and  where  descriptions  are 
seemingly  overdrawn  it  is  easy  after  a  little  experience  to 
select  the  facts. 

Publications  relating  to  the  Hawaiian  Volcanoes. — 
The  earliest  records  of  Hawaiian  lavas  and  of  the  crater  of 
Kilauea  are  contained  in  the  "Journal  of  a  Tour  around 
Hawaii  [in  August,  1823]  by  a  Deputation  from  the  Mission 
of  the  Sandwich  Islands,"  264  pp.  8vo,  with  six  plates,  wdiich 
was  published  at  Boston,  in  1825,  by  Crocker  &  Brewster. 
The  statement  is  made  that  it  was  "  drawn  up  by  the  Rev. 
William  Ellis,"  of  England,  one  of  the  party,  "  from  min- 
utes kept  by  himself  and  by  his  associates  on  the  tour,  who 
subsequently  gave  it  their  approbation."  It  contains,  facing 
page  136,  a  night  view  of  "  the  south  end  of  Kilauea,"  from 


36  VOLCANIC   PHENOMENA. 

a  sketch  taken  by  Mr.  Ellis,  looking  soutliwestward,  en- 
graved by  Mr.  S.  S.  Jocelyn,  an  artist  of  New  Haven,  Conn. 
The  position  from  which  the  sketch  was  taken  is  indicated  in 
the  following  words.  "  Leaving  the  north  end  of  the  crater," 
says  the  ^'Journal"  (p.  145),  ''we  passed  along  to  the  east 
side,  where  Mr.  Ellis  took  a  sketch  of  the  southwest  end  of 
the  crater."  In  the  next  sentence  it  is  added  :  '^  As  we  trav- 
elled from  this  spot  we  unexpectedly  came  to  another  crater," 
nearly  half  as  large  as  the  former.  The  native  name  of  it 
is  Kirauea-iti  (Kilauea-Iki,  as  now  written) ;  ''it  is  separated 
from  the  large  crater  by  an  isthmus  nearly  one  hundred  yards 
wide."  The  position  from  which  the  view  was  taken  was 
hence  north  of  Byron's  hut  (p.  51),  either  on  the  isthmus 
referred  to  or  farther  north  on  the  bluff  adjacent.  A  notice 
of  the  "Journal,"  with  citations,  is  contained  in  the  "Mis- 
sionary Herald,"   1828,  xxii.  28. 

In  1826  a  London  edition  of  the  work,  "  with  large  addi- 
tions," was  issued  by  Mr.  Ellis,  under  the  title  "  Narrative  of 
a  Tour  through  Hawaii ;  "  and  a  third  edition,  of  480  pages, 
was  issued  in  March,  1827.  The  "Narrative"  contains,  facing 
page  226,  a  day  view  of  the  "southwest  end"  of  Kilauea, 
engraved  in  England  from  the  same  sketch  that  was  used  by 
the  American  engraver ;  f(jr  the  remark  a1)out  the  spot  from 
which  it  was  taken  is  repeated  on  page  247.  The  view,  for 
some  unexplained  reason,  is  made  to  differ  widely  from  the 
earlier  ;  for  a  large  cone  stands  where  was  the  foot  of  a 
lava-stream  descending  the  west  wall,  and,  besides  this,  two 
of  the  cones  in  the  bottom  of  the  crater  are  omitted,  and'  the 
active  cones  in  the  crater  emit  vapors  quietly.  These  two 
views  are  presented,  half  size,  on  pages  46,  47. 

Mr.  Ellis  reproduced  his  descriptions  and  his  view  of  the 
crater  in  the  second  edition  of  his  "  Polynesian  Researches," 
which  was  published  in  four  volumes  duodecimo  in  London 
in  1831.  The  earlier  edition  of  the  "Researches."  of  two 
volumes  only,  contained  nothing  about  Hawaii.     In  prepar- 


THE   ISLAND   OF   HAWAII.  37 

ing  the  work  for  the  second  edition,  the  •'  Narrative  "  was 
added  as  the  fourth  volume  ;  and,  for  a  frontispiece  to  this 
volume,  a  new  engraving  of  Kilauea  (from  a  painting,  a 
night  view)  was  introduced,  having  the  subscript.  ''  The  Vol- 
cano of  Kilauea  in  Hawaii.  Sketched  by  W.  Ellis.  Painted 
by  E.  Howard,  Jr.  .  .  .  London,  1831."  An  outline  copy 
of  this  view  is  introduced  beyond,  on  page  50.  It  differs 
widely  from  those  of  1825  and  1826  ;  and  since  the  state- 
ment of  the  ''•  Narrative  "  as  to  where  tlie  sketch  was  taken 
is  again  repeated,  the  source  of  the  differences  has  no  ex- 
planation in  the  work.  The  cones  are  fewer,  but  they  are 
as  active ;  and  one,  placed  out  in  the  front,  is  a  grand  high- 
shooter,  far  outdoing  any  of  those  on  the  other  plates. 
Further,  the  features  of  the  black  ledge  and  the  wall  above 
are  changed  on  both  sides  of  the  pit.  and  the  Great  South 
Lake  is  put  in  a  southeast  recess  instead  of  to  the  southwest. 
Mr.  Ellis  was  a  second  time  at  Kilauea,  but  this  was  before 
1826.  He  then  found  the  crater  much  more  quiet,  and  "  the 
fires  in  the  south  and  west  burning  but  feebly." 

The  next  pul^lication  containing  details  on  the  Hawaiian 
volcanoes  is  the  Rev.  C.  S.  Stewart's  "  Journal  of  a  Voyage 
to  the  Pacific  Ocean  and  Residence  at  the  Sandwich  Islands 
during  the  Years   1822-1825,"  published  in  New  York  in 

1828.  It  contains  an  account  of  a  visit  to  Kilauea,  which 
was  made  on  the  2d  of  July,  1825.  A  citation  from  the 
account  is  contained  in  the  ^'American  Journal  of  Science," 
1826,  xi.   363.     Mr.  Stewart   was    again   at  the   Islands   in 

1829,  and  in  1831  published  in  New  York  his  "  Visit  to  the 
South  Seas,"  in  two  volumes,  duodecimo.  It  is  noticed  in 
the  '•  x\merican  Journal  of  Science,"  1831,  xx.  229. 

In  the  years  1824,  1825,  H.  M.  S.  -'Blonde,"  under  the 
Right  Hon.  Lord  BrROisr,  as  commander,  visited  the  islands ; 
and  at  London,  in  1826,  appeared  his  ''  Voyage  of  the 
*  Blonde'  to  the  Sandwich  Islands,"  in  a  quarto  of  260  pages, 
with  several    plates.      The   visit    to    Kilauea  was  made   on 


38  VOLCANIC   PHENOMENA. 

June  28,  29  (29,  30,  American  time).  It  is  illustrated  by  a 
folded  plate  presenting  a  view  of  the  volcano,  by  R.  Dampier, 
in  which  the  many  cones  give  out  vapors  quietly,  and  also  a 
map  of  the  crater  by  Lieutenant  Malden,  R.  N.    (See  p.  51.) 

Between  1825  and  1841  appeared  in  the  -'American  Jour- 
nal of  Science,"  the  '•  Missionar}'  Herald,"  and  elsewhere,  let- 
ters or  papers  by  Rev.  Joseph  Goodpjch,  dated  1825,  1828, 
1832  ;  by  Rev.  A.  Bishop,  letter  of  1826 ;  by  Rev.  L.  Cham- 
berlain, 1824  ;  by  Messrs.  Chase  and  Parker,  prepared  by 
E.  G.  Kellet,  1838  ;  by  Capt.  John  Shepherd,  R.  N.,  1839  ; 
and  by  Rev.  Titus  Coan,  1840. 

Besides  these,  there  appeared  in  1836,  in  the  "Compan- 
ion of  the  Botanical  Magazine,"  ii.  79-182,  a  memoir  of 
David  Douglas,  by  Dr.  W.  J.  Hooker,  with  a  portrait, 
letters,  and  journal.  Mr.  Douglas  spent  a  dozen  years  in 
travels  over  North  America,  visiting  Oregon,  California,  Hud- 
son's Bay  region,  etc.,  as  an  exploring  naturalist,  and  twice 
visited  the  Sandwich  Islands,  making  collections  and  obser- 
vations in  botany,  zoology,  etc.,  part  of  the  time  under  the 
auspices  of  the  Horticultural  Society  of  London.  His  instru- 
ments included  a  barometer,  chronometers,  a  reflecting-circle, 
large  dipping-needle,  etc.  He  made  his  visit  to  Kilauea  on 
Jan.  23-25,  1834,  and  that  to  the  top  of  Mount  Loa  on  the 
29th  of  the  same  month.  The  account  of  the  latter  journey 
is  contained  in  his  journal  on  page  175  of  the  above-men- 
tioned memoir,  and  in  a  letter  to  Dr.  Hooker  on  page  158. 
Besides,  there  is  an  important  letter  from  him  to  Captain 
Sabine,  dated  Oahu,  May  3,  1834,  taken  partly  from  his 
journal,  but  containing  additional  material  on  his  barometric, 
hygrometric,  thermometric,  and  hypsometric  observations, 
published  in  the  "  Journal  of  the  Royal  Geographical  So- 
ciety," 1834,  iv.  333-334.  Extracts  from  the  journal  of 
Mr.  Douglas  are  contained  in  the  "  Magazine  of  Zoology 
and  Botany,"  1837,  i.  582,  which  includes  the  letter  to 
Dr.  Hooker  describino;  Mount  Loa.     While  on  an  excursion 


THE   ISLAND    OF   HAWAII.  39 

over  Hawaii  in  Jul}",  1834,  Mr.  Douglas,  then  thirty-live 
years  old,  fell  into  a  pit  n^acle  to  entrap  wild  cattle  and  was 
gored  to  death. 

In  the  year  1838  Count  Strzeleoki  visited  Kilauea ;  and 
in  his  ''New  South  Wales  and  Van  Diemen's  Land,"  published 
in  London  in  1845,  he  has  an  account  of  his  observations 
cited,  in  quotation  marks,  from  his  "  manuscript  notes."  The 
"  Hawaiian  Spectator,"  i.  436,  contains  a  note  from  him  on 
tlie  subject,  with  a  different  statement  of  the  facts.  (See 
p.  61.) 

The  author's  first  observations  on  the  Hawaiian  Islands 
were  made  in  the  months  of  October  and  November  of  1840, 
and  during  ten  days  in  November  of  1841,  while  connected 
with  the  Wilkes  Explcring  Expedition  around  the  world,  and 
they  are  reported  upon  in  his  "  Expedition  Geological  Re- 
port," published  by  the  Government  in  1849.^  They  occupy 
pages  155-284  and  353-456,  where  they  are  illustrated  by 
a  colored  geological  map  of  Oaliu  and  many  figures  in  the 
text.  The  islands  studied  were  Oahu,  Kauai,  and  Hawaii, — 
the  last  as  far  as  could  be  done  in  the  commander's  allotted 
week.  A  second  visit  was  made  in  August  and  part  of 
September,  1887,  when  further  observations  were  made  on 
Hawaii  and  Oahu,  and  the  volcanic  mountains  of  Maui  were 
for  the  first  time  visited.^ 

Capt.  Charles  Wilkes  also  has  a  report  on  the  Hawaiian 
volcanoes  in  Volume  IV.  of  his  *'  Narrative  of  the  Exploring 
Expedition,"  published  in  1845,  in  five  volumes,  royal  octavo. 
The  account  given  is  partl}^  his  own  and  partly  that  of  his 
officers,  including  the  excellent  and  faithful  artist  of  the  ex- 
pedition, Mr.  J.  Drayton. 

^  Geology,  756  pages,  4to,  with  a  folio  atlas  of  twenty-one  lithograpliic  plates. 

^  The  facts  observed  in  this  second  visit  are  reported  upon  in  the  "American 
Journal  of  Science,"  in  a  "  Memoir  on  the  Volcanoes  and  Volcanic  Phenomena  of  the 
Hawaiian  Islands,"  published  in  vols,  xxxiii  -xxxvii.  This  memoir  is  closed  by  a 
paper  by  Prof.  E.  S.  Dana  on  the  petrology  of  the  islands  :  and  its  contents  are  re- 
produced in  this  volume. 


40  VOLCANIC   PHENOMENA 

After  1849,  Rev.  Titus  Coan"  became  the  chronicler  of 
the  Hawaiian  volcanoes ;  and  very  much  is  due  him  for  his 
laborious  excursions,  and  his  many  accounts  of  the  volcanic 
changes  in  progress  and  of  the  great  eruptions  of  Kilauea 
and  Mount  Loa.  The  larger  part  of  his  communications  on 
the  subject  appeared  in  the  volumes  of  the  "  American  Jour- 
nal," the  last  in  the  year  1882.  He  also  published  notes  on 
some  of  the  eruptions  in  his  "  Life  on  Hawaii,"  1882.  Ac- 
counts from  other  observers  and  also  many  of  Mr.  Coan's 
appeared  also  in  the  daily  newspapers  of  Honolulu.  Among 
the  most  important  was  a  paper  by  Prof.  C.  S.  Lyman,  in 
the  "  American  Journal  of  Science "  for  1851  (vol.  xii.), 
giving  an  account  of  his  observations  in  1846.  Others  are 
mentioned  beyond,  with  references. 

During  the  years  1864,  1865,  Mr.  William  T.  Brigham 
made  a  study  of  Kilauea  and  Mount  Loa ;  and  he  published 
the  results  of  his  work,  with  maps  and  other  illustrations,  in 
a  memoir  of  126  pages,  quarto,  published  in  1868  in  the 
"•  Memoirs  of  the  Boston  Society  of  Natural  History."  His 
memoir  contains  also  a  map  of  the  crater  of  Kilauea,  from 
a  new  survey  by  himself,  a  history  of  the  Hawaiian  erup- 
tions, and  a  general  review  of  Hawaiian  geology.  He  has 
a  second  paper  in  the  "  Memoirs  of  the  Boston  Society,"  i. 
564,  with  a  map  on  page  572,  based  on  his  own  obser- 
vation and  the  descriptions  of  the  eruption  of  1868.  Mr. 
Brigham  was  again  at  the  islands  in  1880,  and  brief  notes 
by  him  on  the  visit  are  published  in  the  "  American  Jour- 
nal of  Science  "  for  1887. 

In  1882  Capt.  C.  E.  Button  studied  portions  of  the 
islands,  including  especially  Hawaii  and  Maui.  His  account 
of  his  observations,  with  plates  and  maps  in  illustration,  to- 
gether with  discussions  on  points  in  the  science  of  volcanoes, 
covers  140  pages  in  the  "Fourth  Annual  Report  of  the  Direc- 
tor of  the  United  States  Geological  Survey,  1882-1883." 

In  1885  Rev.  J.  M.  Alexander  surveyed  and  mapped  the 


IN   THE   HISTORY    OF    KILAUEA.  41 

Mount  Loa  crater ;  his  paper  on  the  subject  is  contained  in 
the  "American  Journal  of  Science,"  1888,  voL  xxxvi. 

In  1887,  after  the  eruption  of  Kilauea  in  March  of  1886, 
appeared  important  papers  on  the  condition  of  the  crater 
later  in  the  year  1886  by  Mr.  J.  S.  Emerson  and  Mr.  Frank 
S.  Dodge,  assistants  in  the  Government  Topographical  Sur- 
vey, and  by  Prof.  L.  L.  Van  Slyke,  of  Oahu  College,  in  the 
''  American  Journal  of  Science,"  1877,  xxxiii.  87. 

Another  work  of  much  v;ilue  appeared  at  Honolulu  in 
1887  :  Part  11.  of  "  The  Vestiges  of  the  Molten  Globe  ;  or 
on  the  Earth's  Surface  Features  and  Volcanic  Phenomena." 
By  William  Lowtiiian  Green.  A  volume  of  337  pages, 
with  a  map. 

Besides  the  above  works  and  papers  there  are  traditions  of 
a  violent  eruption  of  Kilauea  in  1789,  which  were  collected 
and  published  in  1843  by  the  Rev.  I.  Dibble,  as  stated 
beyond. 


A.     KILAUEA. 

1.    Kilauea  before  1823. 

Eruption  about  the  Year  1789.  —  The  account  of  the  erup- 
tion of  1789,  or  about  that  time,  was  gathered  from  the 
natives  by  the  Rev.  T.  Dibble  and  published  in  his  "^  History 
of  the  Sandwich  Islands,"  at  Lahainaluna  (Island  of  Maui), 
in  1843.  It  was  taken  by  the  author  from  the  lips  of  those 
who  were  part  of  the  company  and  present  in  the  scene,  and 
is  as  follows  :  The  army  of  Keoua,  a  Hawaiian  chief,  being 
pursued  by  Kamehameha,  were  at  tlie  time  near  Kilauea. 
For  two  preceding  nights  there  had  been  eruptions,  with 
ejections  of  stones  and  cinders.  "  The  army  of  Keoua  set 
out  on  their  way  in  three  different  companies.  The  company 
in  advance  had  not  proceeded  far  before  the  ground  began  to 
shake  and  rock  beneath  their  feet,  and   it  became  quite  im- 

6 


42  VOLCANIC  PHENOMENA 

possible  to  stand.  Soon  a  dense  cloud  of  darkness  was  seen 
to  rise  out  of  the  crater,  and,  almost  at  the  same  instant, 
the  thunder  began  to  roar  in  the  heavens  and  the  lightning 
to  flash.  It  continued  to  ascend  and  spread  around  until  the 
whole  region  was  enveloped,  and  the  light  of  day  was  en- 
tirely excluded.  The  darkness  was  the  more  terrific,  being 
made  visible  by  an  awful  ghire  from  streams  of  red  and  blue 
light,  variously  combined  througli  the  action  of  the  fires  of 
the  pit  and  the  flashes  of  lightning  above.  Soon  followed 
an  immense  volume  of  sand  and  cinders,  which  were  thrown 
to  a  great  height,  and  came  down  in  a  destructive  shower  for 
many  miles  around.  A  few  of  the  forward  company  were 
burned  to  death  by  the  sand,  and  all  of  them  experienced  a 
suffocating  sensation.  The  rear  company,  which  was  nearest 
the  volcano  at  the  time,  suffered  little  injury  ;  and  after  the 
earthquake  and  shower  of  sand  had  passed  over,  hastened  on 
to  greet  their  comrades  ahead  on  their  escape  from  so  im- 
minent peril.  But  what  was  their  surprise  and  consternation 
to  find  the  centre  company  a  collection  of  corpses  !  Some 
were  lying  down,  and  others  were  sitting  upright,  clasping 
with  dying  grasp  their  wives  and  children,  and  joining  noses 
(the  mode  of  expressing  affection)  as  in  the  act  of  taking 
leave.  So  much  like  life  the}'^  looked  that  at  first  they  sup- 
posed them  merely  at  rest,  and  it  was  not  until  they  had 
come  up  to  them  and  handled  them  that  they  could  detect 
their  mistake."  Mr.  Dibble  adds  :  "  A  blast  of  sulphurous 
gas,  a  shower  of  heated  embers,  or  a  volume  of  heated  steam 
would  sulticiently  account  for  this  sudden  death.  Some  of 
the  narrators,  who  saw  the  corpses,  affirm  that  though  in  no 
place  deeply  burnt,  yet  they  were  thoroughly  scorched." 

The  "  sand  and  cinders  "  of  this  eruption  (the  latter  usually 
called  on  the  island  piimice  -^  on  account  of  its  extreme  light- 
ness, and    first   mentioned  by   Ellis,  who   says   "light  as  a 

^  Pumice  is  the  scoria  of  a  trachytic  or  some  orthoclase-bearing  lava,  with  the 
vesicles  linear. 


IN   THE   HISTORY   OF   KILAUEA.  43 

sponge  "),  are  well  known  to  cover  an  area  of  '"  many  miles  " 
to  the  southwest  of  the  crater  ;  but  the  accounts  of  the  re- 
gion have  said  nothing  about  the  stones  until  the  publication 
of  Prof.  C.  H.  Hitchcock  in  "Science"  of  February,  1887, 
after  his  visit  to  the  crater  in  the  summer  of  1886.  He 
there  reports  that,  •'  standing  at  Keanakakoi,  one  sees  to  the 
southwest  and  south  a  stretch  of  volcanic  sand  and  debris 
fully  equal  in  dimensions  to  Kilauea  itself.  On  examining 
more  closely  the  material  called  "  gravel '  on  the  map,  it  was 
seen  to  consist  of  material  ejected  from  the  volcano,  and 
numerous  lava-bombs  were  picked  up.  Ashes  also  cover  the 
country  to  the  south  and  southwest  over  tlie  Kau  desert  for 
several   miles." 

The  author  was  over  the  region  here  referred  to  in 
1887.  In  accordance  with  Mr.  Dibble's  words  "  many  miles 
around,"  the  deposits  exist  through  the  whole  circuit  of 
Kilauea,  even  the  vicinity  of  the  Volcano  House  ;  and  the 
projection  of  stones  preceded  that  of  the  light  scoria 
("  pumice "),  yet  it  was  itself  preceded  by  a  great  shower 
of  volcanic  ashes  or  sand.  Tlie  stones  are  in  great  numbers 
and  of  large  size  to  the  west  and  northwest  of  the  crater. 
The  deposit  has  its  maximum  thickness  over  a  large  area 
south  and  southwest  of  the  crater,  where  it  is  twenty-five  to 
thirty  feet  thick  and  extends  ten  miles  or  more  away.  It  is 
well  exposed  to  view  along  the  fissures.  The  lower  twenty 
to  twenty-five  feet  of  the  deposit  consist  of  yellowish-brown 
beds  of  tufa,  the  material  very  fine  volcanic  sand  and  hardly 
consolidated.  Above  the  tufa  are  two  to  three  feet  of  a 
coarse  conglomerate  consisting  chiefly  of  stones  ;  and  above 
this  stratum,  a  bed  twelve  to  sixteen  inches  thick  of  closely 
packed  brownisii  sponge-like  scoria  (''pumice"),  in  pieces  half 
an  inch  across  to  two  or  three  inches. 

This  sponge-like  scoria  contains  the  least  possible  amount 
of  solid  matter,  being  about  ninety-eight  and  one-third  per 
cent   air,    the    rest   glass ;    for  the    small   round    cells    have 


44  VOLCANIC   PHENOMENA 

no  walls  except  a  few  slender  threads,  and  it  is  as  light 
as  a  dry  sponge.  (See  p.  163.)  On  acconnt  of  its  light- 
ness it  is  easily  carried  off  by  the  winds  as  well  as  by 
the  sleepiest  of  waters,  and  hence  the  bed  is  often  left  in 
patches. 

The  ejected  stones  vary  in  size  np  to  several  cubic  feet. 
Those  of  one  to  two  cubic  feet  are  common,  many  are  twenty 
to  tliirty,  and  one  seen  by  the  author  on  the  west  side  of 
Kilauea  measured  one  hundred  cubic  feet  and  must  have 
weighed  over  eight  tons.  Part  are  ordinary  volcanic  scoria ; 
but  the  most  of  them  consist  of  the  more  solid  basalt  spar- 
ingly vesicular ;  and  many  of  the  larger  are  of  a  light  gray 
kind  very  slightly  vesicular  or  hardly  at  all  so,  very  sparingly 
chrysolitic,  and  frequently  having  on  the  worn  exterior  a 
faint  banded  appearance  from  alternating  variations  in  com- 
pactness of  texture.  Another  kind  varies  in  color  from 
faintly  reddish  to  gray,  is  more  or  less  vesicular,  and  con- 
tains a  large  amount  of  chrysolite. 

Going  from  the  southwest  border  northward  and  approach- 
ing the  highest  point  on  the  west  side,  the  Uwekahuna  sta-- 
tion  of  the  survey,  the  deposit  becomes  thinner,  but  retains 
well  its  characteristics.  North  of  this  station  the  thickness 
becomes  ten  feet  and  less.  At  the  Volcano  House  it  is  six 
feet  or  more.  It  may  be  seen  in  front  of  the  house  at  the 
first  descent,  where  it  includes,  at  bottom,  a  bed  of  pebbles  ; 
upon  this,  six  to  eight  inches  of  the  spongy  scoria  ("pumice  ") ; 
then  another  pebbly  layer  and  some  fine  tufa.  It  occurs  also 
just  north  of  the  Volcano  House  garden,  and  may  be  found 
in  traces  elsewhere  about  the  north  border. 

From  the  south  border  of  the  crater  the  formation  extends 
around  by  the  east  side  not  only  to  Keanakakoi,  but  to  the 
Kilauea-iki  depression,  thinning  northward  as  on  the  west 
side,  but  having  the  same  characteristics,  as  observed  in  the 
spongy  scoria,  the  great  numbers  of  large  stones  and  the 
kinds   of   rock   constitutingr   them.     But   the   stones,  though 


IN   THE   HISTORY   OF   KILAUEA.  45 

mail}'  and  large,  are  of  somewhat  less  size  than  to  the  west 
and  southwest,  and  the  ^'pumice"  to  the  northward  on  this 
windward  side  of  the  crater  is  in  thin  widely  scattered 
patches.  The  tongue  of  land  extending  from  that  side  to- 
ward the  south  end  of  Halema'uina'u,  with  the  words  "gravel 
and  Ijowlders "  over  it  on  the  map,  owes  its  gravel  and 
many  bowlders  to  the  same  source,  as  Professor  Hitchcock 
implies.  The  low  plain  between  Kilauea-iki  and  Kilauea 
fails  of  it ;  but  this  is  owing  to  recent  lava-outflows  over 
the  surface.  The  deep  soil  and  earth  farther  east,  over  a 
region  crossed  by  the  north  and  south  carriage-road  on  the 
route  from  Keauhou  to  the  crater,  bearing  tree-ferns  in  lux- 
uriance, is  probably  an  eastern  portion  of  the  tufa  formation. 
The  greatness  and  violence  of  the  eruption  cannot  be 
doubted.  The  distribution  of  the  ejected  stones,  ashes,  and 
scoria  all  around  Kilauea  seems  to  show  that  the  whole  bot- 
tom of  the  pit  was  in  action  ;  yet  the  southern,  as  usual, 
most  intensely  so.  The  heavy  compact  rock  of  the  stones 
and  the  size  of  many  of  them  indicate  that  the  more  deep- 
seated  rocks  along  the  conduit  of  the  volcano  were  torn  off 
by  the  violent  projectile  action.  It  w^as  an  explosive  erup- 
tion of  Kilauea  such  as  has  not  been  known  in  more  recent 
times. 

2.  Kilauea  from  1823  to  1841. 

The  recorded  history  of  the  crater  of  Kilauea  — "  Lua 
Pele  "  of  the  islanders  —  commences  with  August,  1823,  the 
time  of  the  visit  by  the  deputation  of  missionaries  mentioned 
on  page  35.  A  great  eruption  had  taken  place  in  the  pre- 
ceding spring  between  the  months  of  March  and  June  ;  so 
that  the  condition  was  that  of  the  crater  emptied  and  just 
starting  anew  in  the  preparation  for  the  next  eruption.  The 
fact  as  to  an  eruption  but  a  short  time  before  was  inferred 
by  the  deputation  from  the  existence  of  a  "  black  ledge,"  as 


46 


VOLCAXIC   PHENOMENA 


it  was  then  called,  running  like  a  terrace-plain  around  the 
interior  some  hundreds  of  feet  above  the  bottom  ;  "  for  it 
was  evident,"  says  the  •'  Journal,"  '•  that  the  crater  had  been 
recently  filled  with,  lavas  up  to  the  black  ledge/'  and  that, 
as  Mr.  Goodrich  states  it  in  his  letter  of  April,  1825,-  '"'  the 
black  ledge  was  made  by  the  crater's  being  filled  to  that 
level."  Fortunately  the  deputation  had  one  in  their  num- 
ber, Rev.  j\Ir.  Ellis,  to  make  a  sketch  of  the  crater,  and  show 
precisely  what  was  to  be  understood  by  the  description.  A 
reduced  copy  of  the  sketch  as  engraved  for  the  "  Journal  "  is 
here  presented,  and  it  is  conclusive  as  to  the  evidences  of  a 


The  South  End  of  Kilauea. 

recent  eruption  ;  for  it  has  nearly  the  same  features  as  the 
sketch  by  Drayton  made  a  little  more  than  six  months  after 
the  eruption  of  1840.  And  the  resemblance  extends  not 
merely  to  the  black  ledge  and  the  lower  pit,  but  also  to  the 
position  of  the  place  of  greatest  activity  in  the  southwest 
portion.  The  time  of  the  eruption  is  inferred  from  informa- 
tion obtained  in  Kapapala,  a  few  miles  to  the  southwest  of 
Kilauea,  that  the  steaming  chasms,  fresh  ejections  of  lavas, 
and  a  great  sunken  area  fifty  feet  deep  which  the  deputation 
passed  near  Ponahoahoa  were   made  ''  two   moons  "  before 


^  Goodrich,  American  Journal  of  Science,  1826,  xi.  2. 


IN  thp:  history  of  kilauea. 


47 


their  visit  to  the  2)hice,  or,  as  reported  to  them  at  Keara- 
komo,  "  five  moons  ;  "  and  they  add  :  '•  Perhaps  the  body  of 
the  lava  that  had  filled  Kilauea  up  to  the  black  ledge  .  .  .  had 
been  drawn  off  bv  this  subterranean  channel."  '  The  resfion 
is  one  over  which  steaming  chasms  have  been  made  also  at 
later  eruptions  of  Kilauea.  Further,  Rev.  Mr.  Bishop  was 
informed  by  a  native,  in  1826,^  that  ''after  rising  a  little 
higher  the  lava  would  discharge  itself  toward  the  sea,  as 
formerly  by  an  underground  way,"  —  thus  recognizing  as 
a  traditional  fact  what  has  been  fully  sustained  by  later 
events. 

The  following  is  a  copy  of  the  view  of  Kilauea  inserted  in 
the  English  reproduction  of  the  "Journal  "  called  the  "Nar- 
rative." In  spite  of  the  changes  it  tells  the  same  story  as 
to  the  deep  lower  pit  and  the  black  ledge. 


The  Southwest  End  of  Kilauea. 

All  the  changes  are  unfortunate  because  they  tend  to  dis- 
credit the  descriptions.  But  it  is  quite  evident  that  the 
engraver  is  accountable  for  them.  Two  others,  besides  those 
mentioned  on  page  36,  are  here  alluded  to,  that  the  reader 
may  draw  no  wrong  conclusions.     The  lavas  of  the  floor  of 


^  Journal  of  a  Tour,  etc.,  yip.  117,  151. 

2  Bishop,  Mi.ssionaiy  Herald,  xxiii.  53,  after  a  visit  in  1826. 


48  VOLCANIC   PHENOMENA 

the  crater  are  represented  to  be  in  "'  tumultuous  whorls,"  to 
correspond  evidently  with  an  expression  in  Mr.  Ellis's  de- 
scription ;  but  the  engraver  was  probably  not  aware  that  he 
had  made  them  hundreds  of  feet  in  diameter.  The  distant 
southwest  part  of  the  crater  has  its  intense  fires  extinguished, 
and  the  wall  beyond  brought  forward  and  made  definite,  to 
the  loss  of  the  most  characteristic  feature  of  Kilauea. 

There  is  no  reason  to  doubt  that  the  crater,  although  so 
little  time  had  elapsed  since  the  eruption,  was  in  a  state  of 
intense  activity,  and  yet  not  so  generally  flooded  with  lavas 
that  descent  into  it  was  impossible.  The  description  in  the 
"  Journal  "  says  :  ''  The  southwest  and  northern  parts  of  the 
crater  were  one  vast  flood  of  liquid  fire,  in  a  state  of  terrific 
ebullition.  .  .  .  Fifty-one  craters,  of  varied  form  and  size, 
rose  like  so  many  conical  islands  from  the  surface  of  the 
burning  lake.  Twenty-two  constantly  emitted  columns  of 
gray  smoke  or  pyramids  of  brilliant  flame  [lava-jets  ?],  and 
many  of  them  at  the  same  time  vomited  from  their  ignited 
mouths  streams  of  florid  lava,  which  rolled  in  blazing 
torrents  down  their  black,  indented  sides  into  the  boiling 
mass  below."  In  a  night  scene  "  the  agitated  mass  of 
liquid  lava,  like  a  flood  of  metal,  raged  with  tumultuous 
whirl,"  and  "  at  frequent  intervals  shot  up,  with  loudest 
detonations,  spherical  masses  of  fusing  lava  or  bright 
ignited  stones,"  some  of  which  projected  stones  are  rep- 
resented in  the  sketch  (p.  46).  Descending  to  the  black 
ledge  (p.  144),  they  ''  entered  several  small  craters,  .  .  . 
bearing  marks  of  very  recent  fusion,  .  .  .  and  many  which 
from  the  top  had  appeared  insignificant  as  molehills  " 
proved  to  be  "  twelve  or  twenty  feet  high."  ^  They  also  col- 
lected the  "  hair  of  Pele,"  and  afterwards  found  some  of  it 
seven  miles  south  of  the  crater,  ''  where  it  had  been  wafted 
by  the  winds."  Mr.  Ellis  argues,  from  the  ''conical  islands," 
that  the  boiling  caldron  of  melted  lava  ''  was  comparatively 

1  Journal,  pp.  131,  136,  144. 


LN    THE    HISTORY    OF    KII.AUEA.  49 

shallow,"  implying  that  the  cones  stood  on  the  solid  bottom 
of  the  lake.^  Tlie  "  Journal,"  after  describing  on  page  144 
long,  covered,  tunnel-like  chambers  occupying  the  emptied 
interiors  of  lava-streams,  the  upper  surface  rippled,  the  roof 
'•  hung  with  red  and  brown  stalactitic  lava,"  and  "  the  bot- 
tom one  continued  glassy  stream,"  —  words  that  picture  well 
the  hundreds  of  such  tunnel-like  caverns  in  the  lava-streams 
of  the  mountain,  —  says  that  they  followed  one  such  covered 
way  "  to  the  edge  of  the  precipice  that  bounds  the  great 
crater,  and  looked  over  the  fearful  steep  down  which  the 
fiery  cascade  had  rushed,"  the  fall  "  several  hundred  feet." 
The  sketch  on  page  46,  from  the  ''  Journal,"  represents 
rudely  such  a  stream  descending  the  ivest  wall  (like  that  of 
1832,  on  the  opposite  side  of  the  crater) ;  but  it  is  omitted 
from  the  sketch  in  tlie  "  Narrative  "  (see  p.  47).  It  was  prob- 
ably a  fact,  but  was  given  too  great  prominence  in  the  view 
as  engraved  for  the  '•  Journal." 

Mr.  Goodrich's  letter  of  April,  1825,  does  not  distinguish 
the  events  of  his  hrst  four  visits.  He  observes  that  in  Feb- 
ruary, 1825,  he  counted  twelve  places  where  the  lava  was 
red-hot,  and  three  or  four  where  it  was  ''  spouting  up  lava 
thirty  or  forty  feet,"  and  mentions  the  escape  of  vapors 
in  many  places,  making  ''a  tremendous  roaring," — thus 
describing  fully  without  naming  true  ''blow-holes"  and 
"blowing-cones."  On  Dec.  22,  1824,  a  crater  opened  in 
the  bottom,  where  the  lavas  boiled  like  a  fountain,  with 
jets  forty  to  fifty  feet  high,  and  flowed  off  fifty  or  sixty 
rods. 

In  order  to  give  completeness  to  the  records  a  copy  of  the 
engraving  in  Ellis's  "  Polynesian  Researches "  is  introduced 
on  page  50.  A  painter  has  intervened  between  the  sketcher 
and  the  engraver ;  and  the  consequence  is  easily  perceived  ,by 
the  reader  without  remark.     The  black  ledge  is  still  a  char- 

^  Journal,  p.  226,  ami  Narrative,  p.  237. 

7 


50 


VOLCANIC    PHENOMENA 


acteristic  feature,  thougli  made  very  narrow.  It  is  obvious 
that  the  high-shooting  cone  in  the  foreground,  blowing  to  a 
height  of  seven  or  eight  hundred  feet  (measuring  it  by  the 


The  Volcano  of  Kilauea. 


height  of  the  upper  wall),  is  the  artist's  idea.     It  is  wholly 
un-Kilauean,  and  fundamentally  out  of  place. 


Depth  of  the  Lower  Pit  and  Width  of  the  Black  Ledge.  — - 
The  depth  of  the  lower  pit  in  August,  1823,  was  estimated 
by  the  deputation  at  three  or  four  hundred  feet,  and  the 
total  depth  of  the  crater  from  seven  to  eight  hundred  feet, 
making  the  former  nearly  or  quite  half  the  latter.  Mr. 
Goodrich,  who  was  at  the  crater  with  the  deputation  in 
1823,  and  also  three  times  afterward  before  April,  1825, 
estimated  the  whole  depth  at  over  a  thousand  feet,  and  that 
of  the  lower  pit  at  five  hundred  feet. 

On  this  point  and  others  we  have  further  testimony  from 
a  map  and  a  sketch  of  the  crater,  besides  descriptions,  in  Lord 
Byron's  "  Voyage  of  the  Blonde."     Lord  Byron's  party  was. 
at  Kilauea  in  the    last   week  of   June,  1825,  —  nearly  two 
years  after  Mr.  Ellis  drew  his  sketch.     The  map  is  from  a 


IN   THE   HISTORY   OF    KILAUEA. 


51 


survey  by  Lieutenant  Maiden,  R.  N.  The  copy  here  given, 
reduced  one  third,  represents  a  narrow  black  ledge  (5) 
around  the  lower  pit,  with  a  steep  wall  between  them.     The 


height  of  this  lower  wall,  or  the  depth  of  the  lower  pit,  was 
estimated  by  Lieutenant  Maiden  at  four  hundred  feet ;  and 
by  triangulation  he  obtained  nine  hundred  feet  for  the 
height  of  the  upper  wall.  The  calculation  of  the  latter  was 
based  on  the  angle  S''  55',  subtended  by  the  highest  part  of 
the  northwest  wall  (at  7  on  the  map)  from  the  Hut  on  the 
east  side, — ^Lord  Byron's  place  of  encampment,  —  and  the 
distance  obtained  in  his  survey  of  the  point  7  from  the  Hut, 
namely,  8,209  feet.  He  states  that  the  result  gave  932  feet. 
But  there  is  some  slip  in  the  figures  ;  for  the  correct  height 
from  the  data  would  be  851  feet.  The  recent  government 
survey  of  Kilauea  makes  the  distance  across  8^750  feet; 
and  using  this  number,  we  get  907  feet  for  the  height  of 
the  wall.     It  is  therefore  probable  that  900  feet  was  about 


52  VOLCANIC   PHENOMENA 

the  heiglit  of   the  upper  wall,  and   that  the  lower  pit  two 
years  after  Ellis's  visit  had  still  a  depth  of  4(J0  feet. 

The  sketch  of  the  crater  in  Lord  Byron's  "  A^oyage  "  was 
by  R.  Dampier.  It  makes  the  frontispiece  to  the  volume. 
The  following  is  a  copy  reduced  two  thirds.  It  was  evi- 
dently taken  from  the  Hut,  on   the  east  side  of   the  crater. 


KiLAUEA. 

It  shows  the  lower  pit  surrounded  by  a  narrow  terrace-plain, 
or  black  ledge,  and  the  floor  with  some  small  cones  over  its 
surface,  but  with  the  fires  chiefly  in  the  southwestern  part,  — 
that  of  Halema'uma'u,  —  and  with  the  great  dome  of  Mount 
Loa  in  the  background.  Lord  Byron's  "  Voyage  "  states  that 
*'  fifty  cones  of  various  height  appeared  below,"  at  least  "  one 
half  of  these  in  activity  ; "  and  Mr.  R.  Dampier's  sketch 
represents  such  a  scene.  Lieutenant  Maiden's  map  makes 
the  cones  fewer  and  very  broad.  His  crater  No.  5  is  prob- 
ably Halema'uma'u,  for  the  distance  from  the  Hut  is  right 
for  it;  and  if  so,  the  part  ''concealed  by  smoke"  was  of 
much  less  extent  than  was  supposed  by  the  party. 

Rev.  C.  S.  Stewart,  the  author  of  a  '*  Journal  of  a  Voyage 
to  the  Pacific  and  Residence  at  the  Sandwich  Islands  in  1822 
to  1825,"  was  with  the  party  from  the  "  Blonde,"  and  con- 
firms the  statement  in  the  "  Voyage  "as  to  the  number  of 
*'  conical  craters  "  and  the  position  of  the  chief  seat  of  action 
in  the  southwest  extremity  of  the  crater.  The  black  ledge 
is  described  as  covered  with  tortuous  streams  of  shining  lava, 


IN   THE   HISTORY  OF    KILAUEA.  53 

bearing  "  incontestible  evidence  of  once  having  been  the  level 
of  the  fiery  flood ;  "  and  it  is  added  with  reference  to  the  lower 
pit  that  "  a  subduction  of  lava  "  had  "  sunk  the  abyss  many 
hundreds  of  feet  to  its  present  depth."  A  cone  on  the  bot- 
tom, visited  by  the  party,  spoken  of  as  "•  one  of  the  largest, 
.  .  .  whose  laborious  action  "  had  attracted  attention  during; 
the  night  (No.  1  on  Maiden's  map),  was  judged  to  be  one 
hundred  and  fifty  feet  high,  —  ""a  huge,  irregularly  shapen, 
inverted  funnel  of  lava,  covered  with  clefts  and  orifices,  from 
which  bodies  of  steam  escaped  with  deafening  explosions, 
while  pale  flames,  ashes,  stones,  and  lava  were  propelled  with 
equal  force  and  noise  from  its  ragged,  yawning  mouth."  The 
following  night  crater  No.  3  became  suddenly  eruptive,  and 
a  lake  of  fire  (No.  4  ?)  perhaps  two  miles  in  circumference 
opened  in  the  more   distant  part. 

The  black  ledge  is  represented  as  narrow  in  all  the  published 
sketches,  but  most  so  in  Maiden's  map,  and  in  the  view  in 
Ellis's  '*  Polynesian  Researches,"  which  had  the  benefit  of  im- 
provements from  a  professional  artist.  As  the  latter  work 
was  published  five  years  after  the  "  A^oyage  of  the  Blonde," 
it  may  be  queried  whether  Mr.  Howard,  the  painter,  derived 
any  ideas  from  Dampier's  sketch  ;  but  the  following  facts  are 
rather  against  this:  Mr.  Goodrich,  in  his  letter  of  1825,  who 
shows  careful  work  in  his  measurements  of  the  circumference 
of  the  crater  ivitli  a  line,  remarks  that  the  ledge  "  is  like  a 
stair,  although  it  is  half  a  mile  wide  some  part  of  the  way."  ^ 
By  his  measurements,  in  which  he  was  assisted  by  Mr. 
Chamberlain.^  lie  made  the  circumference  of  Kilauea  seven 
and  a  half  miles,  which  is  the  length  on  the  recent  govern- 
ment map,  and  that  of  the  black  ledge  (going  only  half-way 
around  and  estimating  for  the  rest)  five  and  a  half  miles, 
which  also  was  probably  very  nearly  right. 

*  Goodrich,  American  Journal  of  Science,  1826,  xi.  2. 

2  Rev.  L.  Chamberlain,  Ibid.,  and  Missionary  Herald,  1826,  xxii.  42;  Ellis's 
Polynesian  Researches,  iv.  253 ;   Philosophical  Magazine,  September,  1826. 


54  VOLCANIC   PHENOMENA 

Lord  Byron,  on  his  descent  into  the  pit,  went  from  the 
northeast  to  the  northwest  side,  and  states  with  regard  to 
the  width  of  tiie  ledge  —  probably  the  part  on  the  north  side, 
or  that  passed  over  —  that  it  varies  from  four  or  five  feet  to 
upwards  of  twenty,  which  supports  the  evidence  from  the 
map  and  sketch  in  his  "'  Voyage ;  "  and  Mr.  Stewart  says 
that  it  was  in  some  places  many  rods  and  in  others  a  few 
feet  wide.  A  direct  measurement  of  the  southwest  part, 
toward  the  sulphur  banks,  was  made  in  June,  1824,  by  Rev. 
E.  Loomis,  with  the  result  "  nearly  fifteen  rods  wide,"  ^  — 
which  is  about  two  hundred  and  fifty  feet. 

It  will  be  observed  tliat,  in  the  above  citations  from  Mr. 
Ellis  and  other  early  writers  on  Kilauea,  the  only  heights  of 
ejections  of  lava  mentioned  are  thirty  to  forty  and  fifty  feet, 
and  of  cones  twelve  feet,  twenty  feet,  and  for  "■  one  of  the 
largest  cones"  one  hundred  and  fifty  feet,  —  which  are 
common  facts  of  later  time  down  to  the  present.  The 
language  of  descriptions  is  sometimes  strong,  but  the  figures 
are  correct. 

This  close  correspondence  between  the  heights  and  char- 
acter of  ejections  given  in  the  earlier  accounts  and  those  of 
recent  years  is  interesting,  inasmuch  as  it  proves  long-con- 
tinued uniformity  with  regard  to  kind  and  quality  of  work, 
even  to  the  blowholes.  The  activity  was,  however,  greater 
and  more  general  than  has  been  witnessed  for  many  years. 
There  are  exaggerations,  but  they  are  mostly  confined  to  the 
pictures  and  to  some  of  the  general  descriptions.  The  esti- 
mates made  were  usually  below  the  truth,  from  honest 
caution. 

Progress  in  the  Filling  of  the  Loioer  Pit.  —  As  early  as 
February,  1825,  Mr.  Goodrich  stated,  in  view  of  the  over- 
flows he  had  observed,  and  the  making  of  a  ''  mound  "  over 
sixty  feet  high  in  six  weeks,  that  the  pit  had  begun  to  fill 

^  Memoir  of  W.  T.  Brigham,  p.  407. 


IN   THE   HISTORY   OF  KILAUEA.  55 

up  ;  ^  and  in  his  letter  of  Oct.  25,  1828,^  he  made  the  pit  to 
have  diminished  in  depth  since  August,  1823,  by  three  or 
four  hundred  feet.  A  year  later,  Oct.  25,  1829,  Mr.  Stewart 
found  the  lavas,  according  to  his  description,^  still  two  hun- 
dred feet  below  the  level  of  the  black  ledge,  —  which  implies 
a  filling  of  four  hundred  feet,  if  the  depth  in  1823  was  six 
hundred  feet,  and  of  six  hundred  if  eight  hundred  feet  deep. 
He  states  that  although  the  crater  was  comparatively  quiet, 
the  bottom  was  crossed  by  a  chain  of  lava-lakes,  one  of  them 
a  mile  wide,  throwing  up  masses  of  lava  fifteen  to  twenty 
feet ;  and  that  there  were  also  six  cones  in  action  in  the 
lower  pit  and  one  on  the  black  ledo-e.  Here  again  the 
height  of  the  ejections  mentioned  is  small.  In  October, 
1830,  the  black  ledge  was  still   distinct.^ 

But  in  November  of  1832  Mr.  Goodrich  writes  that  in 
the  preceding  July  he  visited  Kilauea,  and  found  evidence 
that  "  the  crater  had  been  filled  up  to  the  black  ledge  and 
about  fifty  feet  above  it,  —  about  nine  hundred  feet  in  the 
whole,"  since  he  first  visited  it  (in  1823). 

Eriqjtion  of  1832.  —  Mr.  Goodrich  found  at  his  November 
visit  that  an  eruption  had  taken  place  ;  for  he  continues  : 
"  It  had  now  again  sunk  down  to  nearly  the  same  depth  as 
at  first,  leaving  as  usual  a  boiling-  caldron  at  the  south  end. 
The  inside  of  the  crater  had  entirely  changed.  ...  In  Janu- 
ary preceding  —  about  the  12th  as  nearly  as  I  can  ascertain 
—  the  volcano  commenced  a  vigorous  system  of  operations, 
sending  out  volumes  of  smoke  ;  and  the  fires  so  powerfully 
illumined  the  smoke  that  it  had  the  apjoearance  of  a  city 
enveloped  in  one  general  conflagration.     A  day  or  two  fol- 

^  J.  Goodrich,  letter  of  April  20,  1825,  American  Journal  of  Science,  182(5, 
xi,  2. 

2  Ibid.,  1829,  xvi.  345. 

^  C.  S.  Stewart,  Visit  to  the  South  Seas  (New  York,  1831),  including  an  ac- 
count of  a  visit  to  Kilauea  Oct.  9,  1829  ;  and  American  Journal  of  Science,  1831, 
XX.  229. 

*  H.  Bingham,  Residence  in  the  Sandwich  Islands,  p.  387. 


56  VOLCANIC   PHENOMENA 

lowing  smart  shocks  of  earthquakes  commenced,  six  or  eight 
a  day.  .  .  .  The  earthquakes  rent  in  twain  tlie  walls  of  the 
crater  on  the  east  side  from  the  top  to  the  bottom,  producing 
seams  from  a  few  inches  to  several  yards  in  width,  from  which 
the  region  around  was  deluged  with  lava.  .  .  .  The  chasms  " 
passed  '^  within  a  few  yards  of  where  Mr.  Stewart,  Lord 
Byron,  myself,  and  others  had  slept,"  — the  Hut  on  Maiden's 
map ;  "  so  that  the  spot  w^liere  I  have  lain  quietly  many 
times  is  entirely  overrun  with  lava."  Descending  into  the 
crater  and  going  "  to  the  south  end,  I  found  myself  on  the 
brink  of  a  burning  lake,  —  an  opening  in  the  lava  sixty  to 
eighty  rods  long,  and  twenty  or  thirty  wide,  ■ —  the  whole 
mass  of  liquid  and  semi-liquid  lava  in  which,  about  twenty 
feet  below  the  brink,  was  boiling,  foaming,  and  dashing  in 
billows  against  the  rocky  shore.  The  mass  was  in  motion, 
runnino;  from  north  to  south  at  the  rate  of  two  or  three  miles 
an  hour,  boiling  up  as  a  spring  at  one  end  and  running  to  the 
other.'' 

Depth  of  the  Lower  Pit  after  the  Erujotion. — Mr.  Goodrich's 
statements  above  cited  would  make  the  depth  of  the  lower 
pit  after  the  eruption  of  1832  nearly  nine  hundred  feet,  and 
of  the  crater  from  top  to  bottom  seventeen  hundred  and  fifty 
feet.  There  is  no  published  account  furnishing  data  for  cor- 
recting this  estimate.  By  letter  from  Mr.  W.  D.  Alexander, 
Surveyor-General  of  the  Hawaiian  Islands,  dated  March  2, 
1887,  I  learn  that  his  father.  Rev.  William  C.  Alexander 
(who  arrived  at  the  Sandwich  Islands  in  1832)  visited  the 
crater  Jan.  12,  1833,  four  months  after  Mr.  Goodrich's  visit, 
and  in  his  private  diary  gives  the  depth  of  the  crater  as  two 
thousand  feet.  This  tends  to  confirm  Mr.  Goodrich's  num- 
bers, although  only  a  rough  estimate.  He  says  nothing  of 
any  black  ledge,  except  of  that  at  the  bottom  of  the  two 
thousand  feet ;  and  this  leads  to  the  inference  that  the  ledge 
was  quite  narrow,  as  in  1823. 


IN   THE   HISTORY   OF   KILAUEA.  57 

There  is  other  t'lill  evidence  from  Mr.  David  Douglas's 
"  Journal "  of  the  existence  of  a  lower  pit  and  black  ledge 
after  the  spring  of  1832,  and  thereby  of  the  down-plunge, 
accompanying  a  discharge  of  the  lavas.^  On  Jan.  22,  1834, 
Mr.  Douglas  made  careful  barometric  measurements  of  the 
crater,  all  the  details  of  which,  with  the  calculation,  are 
given  in  his  letter  to  Captain  Sabine.  He  obtamed  for  the 
depth  to  the  black  ledge,  on  the  highest  northwest  side, 
715  feet,  and  to  the  bottom  of  the  lower  pit  1,077  feet,  as 
a  mean  of  two  calculations.  This  makes  the  depth  of  the 
lower  pit  at  that  date  362  feet,  in  addition  to  which  he 
says  that  there  were  forty-three  feet  more  to  the  surface  of 
tlie  liquid  lavas. 

We  thus  know  that  the  down-plunge  was  a  fact  ;  and 
we  have  proof  further  from  the  measurements  of  Mr. 
Douglas  that  the  lower  pit  was  larger  both  as  to  depth 
and  breadth  than  that  of  1840.  Hence  the  eruption  of 
1832  —  instead  of  being  ''a  very  small  one,  only  remark- 
able from  the  fact  that  the  fissure  from  which  it  emanated 
opens  at  a  level  of  more  than  four  hundred  feet  above  the 
present  lava-lakes,"  with,  "  so  far  as  known,  ...  no  sym- 
pathy .  .  .  within  the  lavas  of  Kilauea "  —  was  one  of 
Kilauea's  greatest,  although  not  registered,  so  far  as  known, 
in  any  outside  stream  of  lava. 

Condition  of  the  Crater ;  Filling  of  the  Lower  Pit.  — 
Some  facts  are  cited  on  the  preceding  page  from  Mr.  Good- 
rich with  regard  to  the  condition  of  the  bottom  of  the  crater 
after  the  eruption.  Mr.  Alexander,  while  in  the  crater  four 
months  later,  found  the  lake  in  the  southwest  end  of  the 
lower  pit,  "the  principal  furnace,  not  in  lively  action,"  and 
ascended  much  disappointed  ;  but  by  the  time  he  had  reached 
the    summit  "  the  s;rand    crater    commenced   furious   action, 

^  Memoir  of  D.  Douglas,  Companion  of  the  Botanical  Magazine,  1830,  ii.;  and 
Letter  to  Captain  Sabine,  May  3,  1834  (see  p.  38). 

8 


58  VOLCANIC   PHENOMENA 

spouting  with  a  roaring  sound  streams  of  melted  lava  far 
into  the  air."  The  next  day  he  went  again  to  the  bottom, 
and  direct  to  the  g;reat  boilinsr  caldron  two  and  a  half  miles 
distant,"  and  found  it  "•  three  thousand  feet  long  and  one 
thousand  feet  wide,  tossing  its  fier}^  surges  forty  or  fifty  feet 
into  the  air."  He  went  to  the  brink  of  the  lake,  but  left  it 
on  account  of  the  fumes,  and  three  minutes  afterward  the 
spot  was  covered  with  the  lavas  of  an  overflow,  '*■  which,"  he 
says,  "  seemed  to  pursue  us  as  we  hastened  away."  It  is 
important  to  observe  that  uniformly  the  ''  far  into  the  air  " 
and  similar  expressions  in  the  general  descriptions  of  travel- 
lers become  when  put  in  figures  not  far  from  thirty,  forty, 
or  fifty  feet  of  actual  height. 

Mr.  Douglas,  whose  visit  was  in  1834,  reports  that  he 
found  two  great  boiling  lakes  in  the  crater,  —  a  northern, 
319  yards  in  diameter,  and  a  southern,  1190  X  700  yards  in 
area,  heart-shaped  in  form.  The  great  southern  lake  was 
"  at  times  calm  and  level,  the  numerous  fiery-red  streaks  on 
its  surface  alone  attesting:  its  state  of  ebullition,  when  ag-ain 
the  red-hot  lavas  would  dart  upwards  and  boil  with  terrific 
grandeur,  spouting  to  a  height  which  from  the  distance  at 
which  I  stood  (on  the  west  wall)  I  calculated  to  be  from 
twenty  to  seventy  feet.  Close  by  stood  a  chimney  above 
forty  feet  high,  which  occasionally  discharged  its  steam  as 
if  all  the  steam-engines  in  the  world  were  concentrated  in 
it,"  — a  good  description  of  a  blowing-cone,  though  the  name 
had  not  yet  been  used.  There  were  o'Jier  chimneys  over  the 
bottom,  some  active  and  others  comparatively  quiet.  In 
each  of  the  large  lakes  the  lavas  had  an  apparent  movement 
southward,  the  velocity  of  which  Mr.  Douglas  measured  (by 
throwino;  on  a  block  of  lava  and  seeino:  how  Ions;  it  took 
to  go  one  hundred  yards),  and  found  it  to  be  nearly  three 
and  a  quarter  miles  an  hour.^ 

'  Mr.   Douglas's  testimony  with   regard  to  the  Hawaiian  volcanoes  has   been 
douhted  because  of  bis  incredible  account  of  what  lie  saw  at  the  summit  crater  in  a 


IN   THE   HISTORY   OF   KILAUEA.  59 

Thus  the  filling  of  the  lower  pit  was  again  in  progress  ; 
and  according  to  information  from  Mr.  S.  N.  Castle,  of 
Honolulu,  the  obliteration  was  nearly  complete  by  the  latter 
part  of  August,  1837.  Mr.  Castle  reports  that  he  found 
cones  active  in  all  parts  of  the  crater. 

On  May  8,  1838,  Kilauea  was  visited  by  Captains  Chase 
and  Parker,  and  an  account  of  their  observations  was  written 
out  from  their  statements  by  Mr.  E.  G.  Kelley,  submitted  to 
them  for  approval,  and  afterward  published  in  the  "  Ameri- 
can Journal  of  Science  "  for  1841,^  with  a  plate  from  their 
sketches,  but  redrawn,  unfortunately,  by  a  New  Haven  artist 
who  evidently  had  Vesuvius  in  his  thoughts.  An  outline 
copy  is  here  introduced.  It  was  taken  at  the  south  end 
looking  northeastward,  and  has  the  great  South  Lake  in  the 
foreground.  The  important  fact  is  registered  in  it  that  the 
black  ledge  was  already  nearly  buried.  There  is  none  on 
the  west  or  north  side  ;  and  to  the  left,  instead  of  a  black 
ledge,  there  is  a  depressed  plain,  forty  feet  below  the  general 
level ;  part  of  it  (AA)  was  flooded  by  lavas  after  having  been 
passed  over  by  the  party.  The  crater  was  luuisually  active  ; 
there  were  twenty-six  volcanic  cones,  twenty  to  sixty  feet 
high,  eight  of  them  throwing  out  cinders,  red-hot  lava,  and 
steam,  and  six  lakes  of  lava  including  the  Great  Lake  (C), 
the  last  "  occupying  more  space  than  all  the  rest." 

letter  to  the  eminent  hotanist,  Dr.  Hooker.  But  I  find  that  injustice  has  been  clone 
Iiim.  His  "  Journal "  of  his  visit  to  the  summit,  evidently  written  by  him  at 
the  time  of  his  observations,  represents  the  crater  us  having  been  long  quiet. 
While  at  Honolulu,  over  three  months  later  (May  3j,  he  wrote  Captain  Sabine  on 
his  various  physical  investigations  and  barometric  measurements,  and  gave  him  the 
same  facts  as  to  the  summit  crater  that  he  has  in  his  "  Journal,"  and  partly  in  the 
same  words.  Only  three  days  later  (May  6)  he  wrote  his  letter  to  Dr.  Hooker,  — 
a  reasonable  letter  in  all  parts,  excepting  its  description  of  the  terrific  activity  and 
inmiense  size  of  the  Mount  Loa  crater.  His  words  indicate  a  mixing  up  and  magnify- 
ing of  what  he  had  seen  at  the  Kilauea  and  summit  craters,  which  can  be  explained 
only  on  the  ground  of  temporary  hallncination.  He  may  have  dined  that  day  with 
his  friend  the  British  consul.  Mr.  Douglas  was  an  excellent  Scotchman,  and  all 
the  rest  of  his  writings  are  beyond  questioning. 
^  American  Journal  of  Science,  1841.  xl.  117 


60 


VOLCANIC   PHENOMENA 


Not  far  from  the  centre  of  the  Great  Lake  an  island  (I)  of 
black  solid  lava  "  heaved  up  and  down  in  the  liquid  mass," 
and  "'  rocked  like  a  ship  on  a  stormy  sea."  This  is  the  first 
mention  of  a  "  floating  island."     The  descending  streams  at 


KiLAUEA,  from  the  south  end. 


B  are  described  as  streams  of  sulphur ;  but  as  this  is  not 
possible,  they  were  probably  lava-streams  in  part  colored 
yellow. 

We  have  still  another  account  for  the  same  year  ;  it  is 
that  of  Count  Strzelecki,  who  was  at  the  crater  in  August  or 
September,  and  published  his  notes  in  his  work  on  "  New 
South  Wales  and  Van  Diemen's  Land,"  in  1845.  He  made 
some  barometric  measurements  over  the  region,  and  deter- 
mined the  height  of  the  north-northeast  wall  down  to  the 
"  boiling  surface  of  igneous  matter  "  to  be  six  hundred  feet, 
and  makes  no  mention  of  a  black  ledge.  He  describes  six 
craters  with  boiling  lavas,  four  of  which  were  only  three  or 
four  feet  high,  a  fifth  forty  feet,  the  sixth  one  hundred  and 
fifty  feet.  He  states  that  the  first  five  contained  twelve  thou- 
sand square  feet  each  ;  while  the  sixth  —  which  he  says  is 
called  "  Hau-mau-mau  "  —  contained  nearly  a    million.     He 


IN   THE    HISTORY   OF  KILAUEA.  61 

alludes  plainly  to  tlie  ebullition  over  this  great  lake  in  tlie 
expression  "  ceaseless  impetuosity  and  fury."  He  says  that 
"  the  lava  sank  and  rose  in  all  the  lakes  simultaneously," 
which  is  not  always   true.^ 

Still  further  evidence  as  to  the  obliteration  of  the  black 
ledge  is  supplied  by  Capt.  John  Shepherd,  R.  N.,  who 
visited  Kilauea  on  Sept.  16,  1839.  Captain  Shepherd  de- 
scended into  the  crater,  and  visited  several  cones  and  small 
lakes  on  his  way  to  the  Great  Lake.  He  speaks  of  the  black 
ledge  as  "  obliterated  ;  "  of  cones  twenty  to  thirty  feet  high; 
whence  issued  vapors  and  lava  with  loud  detonations  ;  of  a 
lake  of  lava  toward  the  east  side  one  mile  long  and  half  a 
mile  wide  within  a  cone  a  hundred  feet  high,  from  the  sum- 
mit of  which  he  saw  the  expanse  of  liquid  lava  "•  in  violent 
ebullition."  He  also  mentions  that  the  lavas  had  an  apparent 
flow  from  south  to  north,  and  adds,  "  caused  by  the  escape  of 
elastic  fluids,  throwing  up  the  spray  in  many  parts  thirty  to 
forty  feet."  ''^ 

Eruption  of  1840.  —  The  eruption  of  1840  had  no  witness 
from  among  the  foreign  residents  of  the  islands.  Mr.  Coan 
was  absent  from  Hilo  at  the  time  on  a  mission  visit  to  Oahu. 
He  states  in  his  letter  on  the  event,  dated  September,  1840,^ 

1  Count  Strzelecki'.s  note  in  the  Huwaiian  "  Spectator "  occurs  in  the  number 
for  October,  1838,  which  number  also  states  that  he  was  visiting  various  por- 
tions of  the  Pacific  in  H.  B.  M.  S.  "Fly."  It  differs  widely  from  the  report 
in  his  own  work,  in  making  the  area  of  the  largest  lake  three  hundred  thou- 
sand square  yards,  and  those  of  the  smaller  "  about  fifty-seven  hundred  square 
yards  each."  His  volume  is  the  later  publication,  and  should  set  aside  the  news- 
paper note.  Count  Strzelecki  in  this  volume  describes  the  terraces  around  the 
Kilauea  crater  as  vast  platforms  ;  makes  the  height  above  the  sea-level  of  the  north- 
northeast  side  of  Kilauea,  two  paces  from  the  edge  of  the  precipice,  4,109  feet 
above  tide-level,  and  600  feet  above  the  fires  below  ;  and  observes  that  this  is  950 
feet  below  the  brim  of  the  ancient  crater,  the  highest  point  of  which  he  made  5,054 
feet,  and  its  circuit  twenty-four  miles.  He  thought  he  saw  evidence  that  this  greater 
crater  was  formerly  brimful  of  molten  lava.  If  this  highest  point  was,  as  is  prob- 
able, that  now  highest  on  the  west  side,  his  observed  height  would  imply  a  large 
subsidence. 

-  London  Athena;um,  Nov.  14,  1840,  p.  909. 

^  Missionary  Herald,  xxxvii.  283. 


62 


VOLCANIC   PHENOMENA 


that  "  on  the  testimony  of  many  natives"  for  a  week  previ- 
ous to  the  eruption,  in  the  latter  part  of  May,  the  interior  of 
Kilauea  was  ''  one  great  sea  of  liquid  lavas,"  and  that  the 
ground  about  Kilauea  so  trembled  from  the  action  below 
that  the  islanders  avoided  the  path  along  the  verge  of  the 
crater. 

On  his  first  visit  in  September,  tliree  months  after  the 
eruption,  he  found  the  crater  witli  a  deep  lower  pit  and  a 
terrace-plain  or  black  ledge  around  the  whole  interior.  Dray- 
ton's sketch  (Plate  II.),  tiioagli  made  four  months  later, 
represents  closely  the   scene. 

Mr.  Coan  gathered  facts  showing  that  the  eruption  began 
on  May  30,  made  itself  apparent  at  intervals  down  the  eastern 
slopes  of  the  mountain,  finall}^  broke  out  as  a  stream  twelve 
miles  from  the  coast,  and  llovv^ed  into  the  sea  just  south  of 
Nanawale ;  and  that  the  flowing  continued  for  three  weeks. 
There  was  no  earthquake,  no  shaking  of  the  mountain.  At 
Hilo  not  the  faintest  rumbling  was  heard  or  felt,  and  only 
slight  quiverings  to  the  north.  A  light  was  seen  in  the  dis- 
tance ;  but  there  were  no  inhabitants  in  the  region,  and  it  was 

supposed  to  be  a  jun- 


gle  on  fire.  The  la- 
vas appeared  first  in 
a  small  pit-crater  five 
miles  southeast  of  Ki- 
lauea (A,  in  the  ac- 
companying map, 
which  is  a  reduced 
copy  of  part  of  a  large 
map  in  the  Atlas  of 
Wilkes's  "•Narrative").  The  natives  stated  that  the  lavas 
rose  to  a  height  of  three  hundred  feet  in  the  crater,  and 
this  was  confirmed  by  the  scoria  within  it.  Next  followed 
small  ejections  over  the  surface  near  by,  where  other  fis- 
sures had  opened,  and  simultaneously  the  lava  of  the  crater 


IN  THE   HISTORY  OF   KILAUEA.  63 

sunk  and  disappeared.  Other  small  openings  and  ejections 
occurred  near  C,  m,  and  ii ;  and  finally,  on  June  1,  began 
the  large  flow  that  was  continuous  to  the  sea,  which  it 
reached  on  June  3,  extending  the  coast-line  outward  nearly 
a  fourth  of  a  mile,  and  so  heating  the  waters  that  for  twenty 
miles  the  shores  were  strewn  with  dead  fish. 

The  place  of  final  outflow  was  twenty-seven  miles  from 
Kilauea,  and  eleven  from  the  sea ;  and  its  height,  according 
to  Wilkes,  1,244  feet  above  tide-level. 

The  flowing  lava  swept  away  forests  in  its  course,  at  times 
parting  and  enclosing  islets  of  earth  and  shrubbery,  and  at 
other  times  undermining  and  bearing  along  masses  of  rock 
and  vegetation  on  its  surface.  It  plunged  into  the  sea  with 
loud  detonations.  The  burning  lava,  on  meeting  the  waters, 
was  shivered  like  melted  glass  into  millions  of  particles, 
which  were  thrown  up  in  clouds  that  darkened  the  sky  and 
fell  like  a  storm  of  hail  over  the  surrounding  country.  The 
light  "  was  visible  for  over  a  hundred  miles  at  sea,  and  at 
the  distance  of  forty  miles  fine  print  could  be  read  at 
midnight." 

The  author  was  over  the  region  in  the  following  Novem- 
ber. The  stream  consisted  largely  of  the  smoother  lava  or 
pahoehoe,  with  twisted  and  ropy  surface,  as  usual ;  but  there 
were  large  areas  of  aa ,  m  which  huge  blocks  were  piled  to- 
gether, and  in  some  places  slabs  were  laid  with  much  regu- 
larity against  one  another.  Here  and  there  were  miniature 
cones  a  few  yards  in  height,  out  of  which  the  lavas  had 
spouted  for  a  while  after  the  stream  had  flowed  on.  Many 
fissures  and  caverns  were  sending  up  hot  vapors,  and  in  some 
the  rocks  were  yet  glowing  within  a  few  feet  of  the  surface. 

The  islets  of  forest-trees  in  the  midst  of  the  stream  of  lava 
were  from  one  to  fifty  acres  in  extent ;  and  the  trees  still 
stood,  and  were  sometimes  living.  Captain  Wilkes  describes 
a  copse  of  bamboo  which  the  lava  had  divided  and  sur- 
rounded ;  yet  many  of  the  stems  were  alive,  and  a  part  of  the 


64  VOLCANIC   PHENOMENA 

foliage  remained  uninjured.  Near  tlie  lower  part  of  the  flood 
the  forests  were  destroyed  for  a  breadth  of  half  a  mile  on 
either  side,  and  were  loaded  with  the  volcanic  sand;  but  in  the 
upper  part  Dr.  Charles  Pickering  of  the  Expedition  Scientific 
Corps  (both  botanist  and  zoologist)  found  the  line  of  dead 
trees  only  twenty  feet  wide.  The  lava  sometimes,  as  in  other 
eruptions,  flowed  around  stumps  of  trees ;  and  as  the  tree 
was  gradually  consumed  it  left  a  deep  cylindrical  hole,  either 
empty  or  filled  with  charcoal.  Toward  the  margin  of  the 
stream  these  stump-holes  were  innumerable  ;  and  in  many 
instances  the  fallen  top  lay  near  by,  dead  but  not  burned. 
Dr.  Pickering  also  states  that  some  epiphytic  plants  upon 
these  fallen  trees  had  begun  again  to  sprout.  The  rapidity 
witli  which  lava  cools  is  still  more  remarkably  shown  in  the 
fact  tliat  it  was  found  sometimes  hanging  in  stalactites  from 
the  branches  of  trees ;  and  although  so  fluid  when  thrown 
off  from  the  stream  as  to  clasp  the  branch,  the  heat  had 
barely  scorched  the  bark. 

The  lava,  as  stated  by  Wilkes,  issued  from  several  fissures 
along  its  whole  course,  instead  of  being  an  overflow  from  a 
single  opening. 

At  three  spots  on  the  coast,  probably  over  three  opened 
fissures,  the  sands  continued  to  be  thrown  up  until  as  many 


Tufa  Hills,  Nanawale. 

rounded  or  nearly  conical  elevations  were  formed,  the  largest 
of  which  was  found  to  be  two  hundred  and  fifty  feet  in 
height,  and  the  smallest  about  one  hundred  and  fifty  feet. 
They  consist  of  a  finely  laminated  tufa,  like  tufa-craters. 
The  above  figure  shows  the  appearance  of  the  hills  at  the 
time  of  the  author's  visit  in  November  of  1840. 


IN  THE  iiirsTom'  OF  kilaup:a.  65 

These  sand-hills  are  exaiii})les  uf  elevations  thrown  up  sncl- 
denly  over  fissures  of  ernption.  They  consist  of  a  nisty 
yellow  tufa,  distinctly  and  finely  laminated.  The  sea  was 
already  encroaching  on  them  in  the  autumn  of  1840,  and  hrid 
exposed  the  regular  stratification  of  the  interior,  showing.'-  a 
steep  inclination  of  the  layers  outward.  Not  a  trace  of  tilt- 
ing took  place  in  the  rocks  beneath  ;  the  hills  are  simple 
cones  of  eruption  formed  of  ejected  cinders.  The  sands  are 
said  to  have  been  thrown  out  from  the  centre  of  each  hill 
while  in  progress ;  yet  there  was  no  cavity  at  top.  As 
the  molten  lava  met  the  sea  there  was  a  violent  explosion, 
and  an  ejection  of  fragments  which  fell  arottnd  the  centre  of 
eruption  ;  and  owing  to  the  water  which  ascended  and  de- 
scended with  them,  the  structure  became  laminated.  The 
yellow  color  of  the  tufa  is  owing  to  the  action  of  the  steam 
and  water  on  the  augitic  and  chrysolitic  sands,  reducing  some 
part  of  the  iron  to  a  hydrate. 

The  time  of  origin  of  the  several  pit-craters  to  the  soitth- 
east  of  Kilauea  is  not  known.  One  of  them,  Makaopuhi,  has 
the  western  half  about  nine  hundred  feet  in  depth,  according 
to  Rev.  E.  P.  Baker,  and  the  eastern  only  half  this  depth,  — 
the  latter  level  answering  apparently  to  a  black  ledge  or 
terrace. 

Form  and  De'pili  of  the  Crater  after  the  Eruption  of  1840. 
—  The  study  of  the  crater  by  the  Wilkes  Exploring  Expedi- 
tion was  begun  in  December,  1840,  —  more  than  a  month 
after  the  author's  visit,  —  and  completed  in  January,  after 
the  pendulum  experiments  had  been  made  at  the  summit  of 
Mount  Loa.  The  accompanying  map  is  a  reduced  copy  of 
that  published  by  Captain  Wilkes.  The  scale  is  five  thou- 
sand feet  to  the  inch.  K  is  for  Kamohoalii ;  and  B  the  posi- 
tion of  Byron's  Hut.  It  will  be  observed  that  it  has  adjoin- 
ing it  on  the  east  two  smaller  pit-craters,  —  Kilauea-iki,  or 
Little  Kilauea,  and  Keanakakoi,  —  both  inactive  in  1840,  and 

9 


66 


VOLCANIC   PHENOMENA 


of  unknown  time  of  origin.^     Wilkes's  map  makes  the  wall 
of  the  lower  pit  much  too  sloping,  and  the  neck  between  the 


KILAUEA 

U.  S.  EXPL.  EXPED 
1841  J 


Encampmciii  above  the  sea  3970  ft. 
Depth  to  Black  Ledge  650 

to  bottom  342 


main  body  of  the  lower  pit  and  the  area  of  the  Great  Lake, 
Halema'uma'u,  far  too  narrow.  Both  are  better  represented 
in  Drayton's  sketch,  on  Plate  II.  ;  but  the  latter  errs  a  little 

1  The  size  of  these  lateral  pit-craters  is  better  mapped  on  Plate  ITI.  Kilauea- 
iki,  according  to  Mr.  Dodge's  recent  ineasureiuents,  is  3,300  feet  from  east  to  west, 
and  2,800  feet  from  north  to  south,  and  has  a  depth  of  749  feet,  or  the  bottom  is  867 
feet  below  the  Volcano  House  datum.  Keanakakoi  is  1,600  feet  long,  1,100  feet 
wide,  and  approximately  400  feet  deep.     Both  have  nearly  vertical  walls. 

The  name  "  Keanakakoi"  (or  Keana-ka-koi),  applied  on  the  Hawaiian  govern- 
ment map  to  the  small  crater  east  of  the  southern  half  of  Kilauea,  signifies,  as  I  was 
informed  by  an  intelligent  native,  the  "  chipping-stone  pit,"  and  refers  to  the  fact 
that  formerly  a  very  compact  grayish  lava  Avas  obtained  at  its  bottom  and  used  there 
for  the  manufacture  of  stone  implements.  No  such  stone  or  manufacture  has  ever 
existed  at  Kilauea-iki.  This  appears  to  settle  the  question  raised  by  Mr.  Brigham  as 
to  the  correct  application  of  the  latter  name.  The  crater  has  now  a  bottom  of  very 
smooth  recent  lava,  which  our  guide  stated  had  been  ejected  eight  or  ten  years  back  ; 
its  ejection  may  have  occurred,  therefore,  at  the  time  of  the  eruption  of  Kilai;ea 
in  1879. 


IN   THE   HISTORY  OF   KILAUEA.  67 

on  the  other  side,  as  the  walls  are  too  free  from  debris. 
(For  further  remarks  on  the  map  see  page  135.  A  dotted 
line  is  added  in  the  northeast  corner  to  indicate  the  pL^.ce 
of  descent.) 

With  regard  to  the  depth  of  the  crater,  we  iind,  as  tlie 
first  statement  about  it  in  Wilkes's  Narrative/  that  the 
"  black  ledge  surrounds  it  [the  crater]  at  the  depth  of  660 
feet,  and  thence  to  the  bottom  is  384  feet."  Four  pages 
beyond,  it  is  added  that  ''  the  black  ledge  is  of  various 
widths,  from  600  to  2,000  feet."  Later  in  the  volume 
measurements  by  Lieutenants  Henry  Eld  and  Thomas  A. 
Budd  are  also  given.  Lieutenant  Budd  made  the  depth  to 
the  black  ledge  650  feet,  and  thence  to  the  bottom  842 
feet,  ''whence  the  total  depth  992."^  Again,  Lieutenant 
Eld,  it  is  observed,^  was  instructed  to  make  the  measurement 
of  the  depth,  ''  as  I  was  desirous  of  proving  my  oivn  as  well 
as  Lieutenant  Budd's  observations  ;  "  and  then  follows  the 
remark,  ''  The  measurements  coincided  within  a  few  feet  of 
each  other."  Had  the  precise  numbers  obtained  by  Lieu- 
tenant Eld  been  reported  we  might  be  aljle  to  remove  the 
doubts  left  by  the  varying  statements.  But  the  fact  that 
Lieutenant  Budd's  results  are  inserted  by  Captain  Wilkes 
on  his  own  map  of  the  crater  is  a  strong  reason  for  believ- 
ing that  the  coincidence  was  between  the  results  obtained 
by  the  two  lieutenants. 

Condition  of  the  Crater  at  the  Time  of  the  Author  s  Vint  in 
November,  1840. — Although  the' crater  had  been  discharged 
but  six  months  before,  the  Great  South  Lake,  Halema'uma'u, 
was  ao^ain  in  full  ebullition  over  its  surface,  an  area  of  one 
thousand  by  fifteen  hundred  feet,  according  to  measurements 
by  Captain  Wilkes.  Besides,  there  were  two  small  boiling 
lava-lakes. 

1  Narrative  of  the  Exploring  Expedition,  iv.  123. 

2  Ibid.,  p.  175.  '  Ibid.,  p.  179. 


68  VOLCANIC   PHENOMENA 

Still,  to  the  spectator  on  the  northern  brink  of  the  pit, 
all  was  marvellonsly  quiet.  The  lofty  walls  were  horizon- 
tally stratified,  nuich  like  those  of  limestone  along  some 
river-gorges,  and,  in  tlie  view,  were  as  free  as  the  latter 
from  scoria  and  all  else  of  volcanic  aspect.  The  interior 
of  the  crater,  an  area  two  and  a  half  miles  long,  covering 
nearly  four  square  miles,  was  a  desolate  scene  of  bare  rock. 
Instead  of  a  sea  of  molten  lava  '■'  I'olling  to  and  fro  its  fiery 
surge  and  flaming  billows,"  the  only  signs  of  action  were 
in  three  spots  of  a  blood-red  color  which  were  in  feeble 
but  constant  aci:itation,  like  that  of  a  caldron  in  ebullition. 
Fiery  jets  were  playing  over  the  surface  of  the  three  lakes ; 
but  it  was  merely  quiet  boiling,  for  not  a  whisper  was  heard 
from  the  depths.  Aud  in  harmony  with  the  stillness  of  the 
scene,  white  vapors  rose  in  fleecy  wreaths  from  the  pools  and 
numerous  fissures,  and  collected  over  the  large  lava-lake  into 
a  broad  canopy  of  clouds  not  unlike  the  snowy  heaps  that 
lie  near  the  horizon  on  a  clear  day,  though  changing  rapidly 
in  shape  through  constant  accessions  of  cloud  material  from 
below. 

When  on  the  verge  of  the  lower  pit,  a  half-smothered, 
gurgling  sound  was  all  that  could  be  heard.  Occasionally 
a  report  like  musketry  came  from  the  depths ;  then  all  was 
still  again,  except  the  stifled  nmtterings  of  the  boiling  lakes. 

In  a  night  scene  from  the  summit  the  large  caldron,  in 
place  of  a  bloody  glare,  now  glowed  with  intense  brilliancy, 
and  the  surface  sparkled  all  over  with  shifting  points  of 
dazzling  light  like  "  a  network  of  lightning  "  ^  occasioned  by 
the  jets  in  constant  play ;  at  the  start  of  each  the  white  light 
of  the  depths  breaking  through  to  the  surface. 

A  row  of  small  basins  on  the  southeast  side  of  the  lake 
were  also  jetting  out  their  glowing  lavas.  The  two  smaller 
lakes  tossed  up  their  molten  rock  much  like  the  larger,  and 

^  A  comparison  made  by  my  friend  Dr.  Charles  Pickering,  a  man  of  very  exact 
observation  and  measured  words. 


IN   THE   HISTORY   OF   KTLAUEA.  69 

occasionally  there  were  sudden  bursts  to  a  height  of  forty  or 
fifty  feet.  The  broad  canopy  of  clouds  above  the  pit,  and 
the  amphitheatre  of  rocks  around  the  lower  depths  were 
brightly  illumined  from  the  boiling  lavas,  while  a  lurid  red 
tinged  the  more  distant  walls,  and  threw  into  varying  depths 
of  blackness  the  many  cavernous  recesses. 

The  next  night  streams  of  lava  boiled  over  from  the  lake, 
and  formed  several  glowing  lines  diverging  over  the  bottom 
of  the  crater.  Toward  morning  there  was  a  dense  mist,  and 
the  whole  atmosphere  seemed  on  fire.  The  lakes  were  barely 
distinguished  through  the  haze,  by  the  spangles  on  the  sur- 
face that  were  Vjrightening  and  disappearing  with  incessant 
change. 

Reaching  the  black  ledge  we  came  upon  the  scene  of  the 
recent  fires  and  lava-flows,  although  the  boiling  pools  were 
still  three  hundred  and  forty  feet  below.  Streams  of  har- 
dened lava  with  their  tortuous  windings  covered  its  surface, 
some  spreading  far  and  wide  and  ending  in  a  rolled  margin 
against  the  base  of  the  outside  walls  of  the  crater,  and  some 
twisted  into  ropes  or  ropy  lines,  or  reaching  out  in  rounded 
knobs.  Others,  of  less  extent,  surrounded  an  oddly  shaped 
cone,  a  few  yards  in  height,  which  small  worming  streams 
and  smaller  driblets  of  lava  had  raised.  These  features 
were  testimony  to  the  great  lava-floods  that  spread  over  the 
whole  crater,  even  the  black  ledge,  before  the  eruption  of 
the  preceding  June.  Other  reminders  were  the  many  dark 
chasms  along  the  margin  of  the  black  ledge,  some  opening 
to  depths  of  hundreds  of  feet,  and  letting  up  torrents  of 
hot  air  or  suffocating  fumes  of  sulphur.  In  several  places 
acres  of  the  ledge  were  tottering  ready  to  fall ;  and  twice, 
while  among  the  chasms,  long-continued  rumbling  sounds 
broke  the  silence  of  the  pit,  showing  that  the  engulfing 
or  down-plunging  of  the  walls,  that  began  with  the  dis- 
charge of  June,  was  still  in  progress. 

The   great   subsidence  of  nearly  four  hundred  feet  at  the 


70  VOLCANIC   PHENOMENA 

time  of  the  eruption,  making  the  lower  pit,  generally  gave 
the  pit  vertical  walls,  with  no  slopes  except  such  as  were 
formed  of  fallen  masses  of  rock.  But  on  the  northwest 
side,  the  outer  part  of  a  great  block  five  hundred  yards 
along  the  ledge  and  four  hundred  yards  in  mean  width, 
and  hence  two  hundred  thousand  square  yards  in  area, 
sank  down  the  four  hundred  feet  so  as  to  make  a  sloping 
plane  from  the  top  of  the  ledge  to  the  bottom  of  the  pit. 
A  broad  fissure  divided  the  sunken,  sloping  mass  from  the 
black  ledge,  and  other  fissures  intersected  its  surface.  A 
descent  into  the  lower  pit  along  any  part  of  the  vertical 
walls  was  dangerous ;  but   here   it   was   easy.^ 

Over  the  solidified  lava-stream,s  of  the  bottom,  as  well  as 
the  black  ledge,  the  tread  made  the  lava  crackle,  as  if  it 
were  nothing  but  the  loosest  of  fragile  scoria.  The  crack- 
ling was  due  to  a  shining,  glassy  scoriaceous  crust,  two  to 
four  inches  thick,  that  was  crushed  under  the  foot,  and  was 
easily  peeled  off  from  the  more  solid  rock  of  the  lava- 
stream.  Few  visitors  to  the  crater  find  out  that  there  is 
any  other  kind  of  lava  in  the  crater  besides  this  shining 
and  often  iridescent  crust.  It  was  found  to  be  only  the 
scum  of  the  boiling  lava-lakes,  —  the  frothy  part,  which  each 
stream  bore  off,  like  that  on  a  stream  from  a  pot  of  boiling 
molasses. 

Over  the  eastern  of  the  two  small  lava-lakes,  the  first 
visited,  the  lava-jets  darted  to  a  height  of  ten  or  a  dozen 
yards,  and  fell  again  into  the  lake  or  upon  its  sides.  There 
was  no  inconvenience  or  dantrer  in  standing;  within  four  or 
five  feet  of  the  edge  of  the  basin.  The  formation  of  Pele's 
hair,  or  capillary  volcanic  glass,  was  going  on  at  the  time  ;  and 
the  spun  glass  covered  tbickly  the  surface  to  leeward  of 
the  lake,  where   it  lay  like  mown  grass.     On  watching  the 

^  It  is  indicated  as  the  place  of  descent  on  the  Wilkes  map  (p.  66).  In  Dray- 
ton's view  (Plate  II.)  the  line  of  the  sloping  plane  was  coincident  with  the  line  of 
vision,  and  hence  it  does  not  appear. 


IN   THE   HISTORY   OF   KILAUEA.  71 

operation  a  moment  it  was  apparent  that  it  proceeded  from 
the  jets  of  liquid  lava  thrown  up  Ij}^  the  process  of  boiling. 
The  winds  carried  off  the  spun  glass,  and  laid  it  down  over 
the  surface  to  leeward,  the  heavy  or  loaded  end  going  down 
first.  It  apjDeared,  at  the  time,  as  if  the  wind  carried  off 
small  points  of  the  jetted  lavas,  and  thus  drew  out  the 
glassy  hairs  ;  but  others  have  since  shown  that  the  hairs 
are  drawn  out  when  the  projected  lava,  in  its  ascent,  be- 
comes divided  into  a  succession  of  clots,  the  hairs  being  spun 
as  the  pieces  pull  apart,  and  that  the  wind  serves  only  as 
a  transporter. 

The  overflowing  of  the  lava-lake  —  a  common  event  for 
the  smaller  lakes  as  well  as  the  large  —  had  made  a  low  cone 
about  it,  exemplifying  the  process  of  overflow  or  superfluent 
eruptions  characterizing  the  early  period  of  a  volcanic  moun- 
tain. One  such  cone  of  great  breadth  over  the  centre  of  the 
floor,  with  a  large  crater  at  top  but  then  extinct,  had  a 
height  of  about  one  hundred  feet.  The  lavas  of  the  floor 
covered  caves  of  various  sizes,  and  the  roofs  afforded  stony 
stalactites,  some  of  them  of  ordinary  tapering  shapes  and 
others  of  a  slender  cylindrical  form  not  larger  than  a  quill 
and  partly  hollow. 

A  few  hundred  yards  from  the  eastern  lava-lake  there 
stood  a  singular  spire  of  lava,  like  a  petrified  fountain. 
A  column  of  hardened  lava-drops 
had  been  raised  on  a  rudely  shaped 
conical  base,  having  a  height  in  all 
of  about  forty  feet.  It  had  been 
formed  over  a  small  vent,  out  of 
which  the  liquid  rock  was  shot  up 
in  driblets  and  small  jets, — making 
one  of  the  fantastic  driblet-cones,  as 

,-,  ,1  1  .  n     1     ii  Driblet-cone,  November,  1840. 

the  author  has  smce  called  them,  — 

the  result  of  blowing-hole  action.  It  is  an  interesting  exam- 
ple of  a  cone  of    90^    on   one  of   40°  to  70°,   made   out    of 


72  VOLCANIC   PHENOMENA 

descending  lavas, -'but  lavas  in  drops,  the  drops  in  succession 
adhering  to  one  another ;  the  aperture  from  which  those 
of  the  column  were  thrown  out  was  close  by  its  base. 

The  surface  of  the  Great  Lake,  at  the  time  of  the  author's 
exploration  of  the  bottom,  was  fifteen  or  twenty  feet  below 
its  banks,  and  the  height  of  the  jets  appeared  to  be  nearly 
as  many  yards.  The  surface  lavas,  with  the  playing  jets, 
had  apparently,  as  reported  by  Douglas,  a  flow  to  the  south- 
westward.  It  looked  as  if  a  great  lava-stream  came  up  to 
the  surface  for  a  moment  and  flowed  on  ;  but  it  was  appar- 
ent that  it  was  due  to  the  process  of  ebullition,  —  the  lavas 
raised  in  the  hotter  portions  flowing  off  to  the  cooler  side. 

One  of  the  most  striking  sights  in  the  crater  was  that  of 
the  cooled  and  hollow  streams  of  lava  coming  down  the  steep 
walls  just  south  of  the  usual  place  of  descent.  They  were 
those  of  the  eruption  of  1832,  which  flooded  the  plain  above, 
including  the  site  of  Lord  Byron's  ''  Hut,"  and  which  also 
plunged  into  the  crater,  besides  escaping  from  fissures  in  the 
wall.  The  angle  of  descent  of  the  streams  was  about  35° ; 
and  yet  the  streams  were  continuous.  The  ejection  had  been 
made  to  a  height  of  four  hundred  feet  at  a  time  when  the 
pit  below  was  under  boiling  lavas  and  ready  for  discharge. 
Elsewhere  about  the  upper  walls,  and  also  about  those  of  the 
lower  pit,  no  scoria  was  seen.  The  surfaces  of  walls  are  those 
of  fractures,  brought  into  sight  by  subsidences ;  and  the 
rocks  of  the  layers  were  as  solid  as  the  most  solid  of  lavas. 
Moreover,  no  scoria  intervened  between  the  beds  of  lava 
even  in  the  walls  of  the  lower  pit,  each  new  stream  having 
apparently  melted  the  scoria-crust  of  the  layer  it  flowed 
over  ;  and  no  beds  of  cinders  or  volcanic  ashes  were  any- 
where to  be  seen  in  alternation  with  the  beds  of  lava.  While 
the  cooled  lava-streams  over  the  bottom  were  of  the  smooth- 
surfaced  kind,  and  would  be  called  pahoehoe,  there  was  the 
important  distinction  into  streams  having  the  scoria-crust  just 
mentioned,  and  those  having  the  exterior  solid  with  no  sep- 


IN   THE   HISTORY   OF    KILAUEA.  73 

arable  crust,  —  facts  that  pointed  to  some  marked  difference 
in   conditions  of  origin. 

Condition  in  Janaaru,  1841.  —  In  January,  on  the  16th, 
as  observed  by  Captain  Wilkes,  one  of  the  small  lava-lakes, 
called  Judd's  Lake,  sent  forth  a  great  stream  over  the  bottom 
of  Kilauea,  and  on  the  night  after  the  following  day,  Hale- 
ma'uma'u,  the  Great  Lake,  overflowed.  The  next  morning 
the  lavas  had  sunk  one  hundred  feet.  On  the  26th  Dr. 
Pickering  found  the  surface  much  depressed  and  in  ebulli- 
tion throughout;  yet  -"Judd's  Lake  w\as  at  the  same  time 
overfiowiug  its  banks."  Dr.  Pickering  concluded,  from  his 
observations  at  this  time  and  in  December,  that  during  the 
intervening  month  the  bottom  of  "  the  lower  pit  had  been 
raised  at  least  fifty  feet." 

The  crater  had  then  (as  shown  on  the  map,  p.  60;  two 
sulphur-bank  regions.  One  was  situated  on  the  southeast 
side  of  the  crater,  where  the  rocks  of  the  wall  had  been 
crumbled  to  an  earthy  slope  in  consequence  of  their  decom- 
position by  the  hot  acid  fumes.  Fine  crystallizations  of 
sulphur  were  constantly  forming  through  condensations  be- 
neath an  outer  crust  of  the  earthy  surface  ;  and  with  the 
sulphur  there  was  some  gypsum,  a  little  alum  (alumina  sul- 
phate), some  ammonium  sulphate,  and  traces  of  blue  vitriol 
or  copper  sulphate,  the  last  indicating  the  probable  presence, 
in  the  depths  below,  of  the  common  copper  pyrites  or 
chalcopyrite. 

Another  larger  sulphur-bank  region  —  a  true  solfatara  — 
occupied  the  eastern  part  of  the  broad  depressed  area  at  the 
northeast  end  of  the  crater,  —  an  area  intersected  by  many 
profound  chasms  emitting  hot  air  and  water  vapor,  and  some 
of  them  also  fumes  of  sulphurous  acid.  Incrustations  of  the 
blue  copper  sulphate  were  obtained  also  at  this  place.  Toward 
the  margin  on  this  side  of  the  pit  large  sections  of  the  walls 
had  subsided  ;  and  the  way  down  into  the  pit  was  along  such 
sunken  blocks  and  among:  the  steaming  chasms. 


74  VOLCANIC   PHENOMENA 


3.     KiLAUEA    FROM    JANUARY,    1841,    TO    1868    INCLUSIVE. 

The  history  of  Kilauea  thus  far  presented  mckides  three 
great  eruptions  within  the  seventeen  and  a  half  years  between 
the  early  part  of  1823  and  the  summer  of  1840,  with  inter- 
vals of  eight  to  nine  years.  It  also  indicates  that  the  method 
of  change  was,  in  a  general  way,  alike  for  each  interval,  from 
the  emptied  state  of  the  pit  to  that  of  high-flood  level  pre- 
paratory to  discharge  ;  and  alike  in  the  down-plunge  of  the 
floor  consequent  on  the  discharge.  Further,  the  various 
accounts  agree  in  referring  the  filling  of  the  pit  to  outflows 
of  lavas  from  lava-lakes,  cones,  and  fissures  over  the  bottom 
of  the  crater,  and  in  mentioning  no  facts  that  point  to  other 
concurring  means. 

During  the  following  twenty-eight-year  period,  from  1840 
to  1868,  these  several  subjects  received  not  only  contribu- 
tions of  new  facts,  but  the  most  fundamental  of  them,  on 
the  method  of  filling  the  pit,  facts  enough  for  a  widened 
and  apparently  final  explanation.  Even  within  the  first  six 
years  of  the  twenty-eight  the  demonstration  was  made  out, 
though  not  published  until  1851.  The  only  down-plunge  of 
the  floor  in  this  period,  producing  a  lower  pit,  occurred  at  its 
close  in  1868. 

(1)  Changes  in  the  Crater  from  1841  to  1849.  —  The 
changes  after  the  year  1840  went  forward  in  the  usual  quiet 
way,  varying  much  from  time  to  time,  but  on  the  whole 
with  some  increase  in  activity. 

In  July,  1844,  according  to  a  letter  from   Mr.  Coan,^  the 

^  The  letter  nf  Mr.  Coan  has  not  been  published  entire,  and  the  author  is  in- 
debted to  his  son,  Mr.  T.  Munson  Coan,  for  a  copy  received  in  April,  LS8S.  Some 
extracts  from  a  letter  on  the  same  subject  are  contained  in  the  author's  "  Exploration 
Expedition  Report,"  p.  193.  The  complete  letter,  in  connection  with  the  observa- 
tions of  Mr.  Lyman  above  reported,  enables  the  author  to  correct  the  note  about 
the  canals  on  page  84  of  the  ''  American  Journal  of  Science  "  for  July,  1887. 


IN   THE   HISTORY   OF   KILAUEA.  70 

Great  Lake,  Halema'uma'u,  overflowed  its  margin  on  all 
sides,  "  spreading  out  into  a  vast  sea  of  fire,  filling  the 
whole  southern  part  of  the  crater  out  to  the  black  ledge 
on  either  side,  and  thus  obliterating  the  outlines  of  the 
caldron."  Moreover,  the  lavas  flowed  northward  and  north- 
eastward ''  in  tw^o  deep  canals  five  to  fifteen  rods  w^ide,  one 
hundred  feet  deep,  and  tw^o  miles  long,"  —  one  by  either 
margin  of  the  lower  pit  at  the  base  of  its  walls;  and  ''the 
two  came  within  half  a  mile  of  meeting  under  the  northern 
wall  of  the  crater."  ^  In  one  of  these  canals  the  liquid  lava 
plunged  down  a  precipice  of  some  fifty  feet,  forming  "  a  fiery 
cataract  of  indescribable  grandeur." 

The  facts  were  also  observed  by  his  son,  Mr.  Titus  Munson 
Coan,  and  a  similar  record  made  at  the  time.  The  latter 
mentions  also  a  small  lake  in  the  floor  of  the  pit  toward  the 
middle  of  the  west  side. 

A  diagram  by  the  Rev.  Mr.  Coan  accompanies  the  letter. 
It  represents  the  canals  at  the  base  of  the  wall  bound- 
ing the  lower  pit,  and  situ- 
ated close  by  the  black  ledge, 
on  which,  as  is  recorded  on 
tlie  map,  the  two  walked 
at  the  time  around  the  cra- 
ter besides  also  crossing  the 
lower  pit. 

Canals  five  to  fifteen  rods 
or  eighty  to  two  hundred  and 
fifty  feet  wide,  could  not  be 
ordinary  fissures ;  and  their 
position  along  the  sides  of 
the  lower  pit  at  the  foot  of  the  enclosing  walls,  their  depth, 
the  cascade  of  fifty  feet,  their  great  length,  the  two  nearly 
encircling  the  lower  pit,  were  at  the  time  without  expla- 
nation.    The  depth   of  the  lower  pit  is  not  stated. 


1  Coan,  Life  in  Hawaii,  1882,  p    2(13, 


76  VOLCANIC   PHENOMENA 

Two  years  later,  in  June  of  1846,  Mr.  Coan  reported^  that 
*'  the  repeated  overflowings  had  elevated  the  central  parts  of 
the  crater  four  or  five  hundred  feet  smce  1840,  so  that  some 
jDoints  are  now  more  elevated  than  the  black  ledge."  Thus, 
in  only  six  years  the  lower  pit  —  nearly  four  hundred  feet 
deep  in  Jnne  of  1840  —  had  been  almost  or  quite  obliterated. 
It  is  reasonable  to  conclude,  therefore,  that  in  1844  two  thirds 
of  the  original  depth  had  l^een  lost ;  and  hence  that  when 
those  great  canals  existed  alongside  of  the  black  ledge,  the 
lower  pit  was  less  than  one  hundred  and  forty  feet  deep,  ex- 
cept alo?ig  the  ivide  canals.  The  next  record  gives  the  key  to 
the  mystery  about  the  canals.  i 

In  the  course  of  the  next  month,  July  of  1846,  Rev.  Ches- 
ter S.  Lyman  (afterward  Professor  of  Mechanics  and  Physics 
in  the  Sheffield  Scientific  School  of  Yale  University),  visited 
the  crater,  and  found  it  in  the  condition  reported  by  Mr.  Coan. 
The  account  of  his  investigations,  which  he  published  in 
1851,"  states  that  "  the  whole  interior  of  the  pit  had  been 
filled  up  nearly  to  a  level  v/ith  the  black  ledge,  and  in  some 
places  fifty  to  one  hundred  feet  above  it."  Moreover,  Mr. 
Lyman  proved  that  the  change  was  not  a  change  of  level  in 
the  ledge,  instead  of  the  centre  of  the  pit,  by  measuring  a 
base  and  taking,  with  a  quadrant,  the  altitude  above  it  of 
the  high  western  wall,  making  it  six  hundred  and  eighty 
feet,  which  agrees  very  nearly  with  -the  result  of  Wilkes's 
measurement. 

Beyond  all  this,  Mr.  Lyman  obtained  full  testimony  as  to 
the  ivay  in  ichich  the  rapid  obliteration  of  the  pit  had  gone 
forward,  and  thereby  reached  an  explanation  of  the  so-called 


1  Coan,  American  Journal  of  Science,  1850,  x.  361. 

2  American  Journal  of  Science,  1851,  2d  series,  xii.  75.  A  letter  from  Mr. 
Lyman,  dated  Sandwich  Islands,  July,  1846,  is  referred  to  on  page  193  of  the 
author's  "  Expedition  Geological  Report  ; "  but  no  facts  respecting  the  crater  are 
there  cited  except  the  one  that  some  parts  of  the  centre  stand  one  hundred  to  one 
hundred  and  fifty  feet  above  the  black  ledge  ;  the  author  has  no  knowledge  of  what 
it  contained  beyond  this. 


IN   THE   HISTORY  OF   KILAUEA.  77 

canals.  He  found  that  while  the  bottom  of  the  pit  was 
almost  level  with  the  ''  black  ledge,"  there  was  upon  it, 
along  the  inner  rnar<j'ui  of  the  ledge,  "  a  continuous  ridge, 
more  than  a  mile  long,  consisting  of  angular  blocks  of  com- 
pact lava,  resembling  the  debris  at  the  foot  of  a  range  of 
trap  or  basalt,"  and  that  this  ridge  had  a  height  "on  its 
outer  or  eastern  face  often  of  fifty  or  one  hundred  feet 
[above  the  ledge],  especially  toward  the  south  part,  where  it 
approached  the  Great  Lake."  Another  remarkable  feature 
of  related  import  was  the  existence  of  a  trough  or  ^'  canal " 
between  the  ridge  and  the  margin  of  the  ledge,  "  several  rods 
in  width,  and  in  some  places  forty  or  fifty  feet  in  depth,"  — 
the  same  canal  that  had  been  reported  in  1844.  The  ridge 
looked  highest  from  the  black  ledg-e  side,  the  ledc^e  beino; 
lower  than  the  interior  plain.  Following  it  southward,  the 
slope  on  the  interior  side  diminished  in  height,  and  finally 
ran  out,  while  on  the  black  ledge  side  the  elevation  increased 
until  the  slope  became  a  precipice  over  one  hundred  feet  high, 
which  was  so  steep  at  "  its  southeastern  limit  that  stones 
hurled  from  the  hand  cleared  the  foot  of  the  bluff."  The 
stones  were  "  nearly  three  seconds  in  falling,  which  would 
give  for  the  perpendicular  elevation  the  amount  just  stated 
[or  between  one  hundred  and  forty  and  one  hundred  and 
fifty  feet]."     ' 

The  "  canal,"  as  was  learned  from  Mr.  Coan,  had  been  fill- 
ing up.  from  a  y^revious  depth  of  two  hundred  feet,  by  flows 
of  lava  from  the  Great  Lake.  In  July  it  was  nearly  filled, 
and  in  some  parts  obliterated. 

,  After  a  survey  of  the  facts  as  to  the  position  and  nature 
of  the  long  ridge  of  lava-blocks,  and  a  comparison  with  the 
condition  in  1840,  Mr.  Lyman  concluded  that  the  ridge  "once 
constituted  a  talus,  or  accumulation  of  debris,"  on  the  floor  at 
the  foot  of  the  walls  of  the  lower  pit  of  1840  ;  that  the  floor 
with  its  margin  of  blocks  had  "  been  elevated,  partly  by  up- 
heaving forces  from   beneath,  and  partly  by  overflows  from 


78  VOLCANIC  PHENOMENA 

the  Great  Lake  and  other  active  vents,"  until  the  talus  over- 
topped '"  the  precipice  at  the  foot  of  which  it  was  accumu- 
lated." He  adds:  "■  The  phenomenon  seems  inexplicable  on 
any  other  hypothesis  than  that  of  the  hodily  upheamng  of  the 
inner  floor  of  the  crater^  ''  When  visited  by  the  Exploring 
Expedition  in  1840,  the  surface  of  the  Great  Lake  was  be- 
tween three  and  four  hundred  feet  below  the  black  ledge,  and 
measured  only  a  thousand  by  fifteen  hundred  feet  in  diameter. 
Consequently  in  six  years  the  lake  had  not  only  increased  in 
size,  but  it  had  actuallv  risen  in  heierht  as  much  as  it  had 
been  previously  depressed  by  the  out-draining  of  lavas  in  the 
eruption  of  1840.  This  gradual  rising  of  the  solid  embank- 
ment of  the  lake  cotemporaneously  with  the  lake  itself,  to- 
gether with  the  filling  up  of  the  whole  interior  of  the  crater, 
is  doubtless  to  be  attributed  to  the  combined  effect  of  repeated 
overflowing  together  with  the  upheaving  agency  of  subterra- 
nean forces." 

Mr.  Lyman  took  a  few  compass-bearings  in  the  crater,  and 
some  angles  with  a  quadrant  which  he  had  constructed  for 
the  Kilauea  visit,  and  left,  with  a  friend  on  the  Islands,  a 
rapidly  penned  sketch  of  the  crater  showing  the  general  con- 
dition of  the  interior.  A  reduced  copy  of  the  map  with  its 
lettering  is  here  presented.^  The  position  of  the  canal  is 
stated  on  the  map  to  be  ''nearly  up  to  the  black  ledge,  and  in 
places  quite,"  as  in  Coan's  sketch ;  and  it  makes  the  whole 
circuit  of  the  pit.  The  facts  observed  prove  that  the  canal 
was  a  channel  left  between  the  black  ledge  and  the  talus- 
made  ridge,  and  that  it  was,  hence,  an  incident  in  the 
elevation. 

The  ''  Furnace,"  marked  on  the  map,  is  described  in  his 
paper  as  oven-like,  ten  or  twelve  feet  high,  with  walls  a  foot 
thick;  as  being  inactive  but  showing  within  a  glowing  white 
heat  early  in  July,  but  "  in  full  blast  "  at  his  second  visit  in 
August,  six  weeks  later.     The  large  depression  in  the  crater, 

1  American  Journal  of  Science,  1887,  xxxiv.  8.5,  and  1888,  xxxv.  24. 


IN   THE   HISTORY   OF   KILAUEA. 


79 


which  contained  steaming  fissures  and  chasms,  appeared  to 
have  been  the  site  of  a  former  lava-lake. 

Kilauea,  at  the  time  of  Mr.  Lyman's  visit,  was  only  mod- 
erately active.  The  diameters  of  the  Great  Lake  were  twenty- 
four  hundred    and  two    thousand   feet.       Over    its    surface. 


ten  or  fifteen  feet  below  the  brim,  on  which  he  stood,  the 
lavas  were  in  gentle  ebullition,  tossing  up  broken  jets  five  to 
fifteen  feet,  and  passing  through  frequent  transitions  between 
a  crusted  and  a  wholly  molten  state.  It  is  evidence  of  rela- 
tively feeble  activity  that,  standing  on  the  brink,  a  handker- 
chief before  the  face  was  sufficient  to  shield  it  from  the  heat. 
In  November  of  1840  it  was  hardly  possible  to  walk  on  the 
black  ledge  abreast  of  the  lake,  on  account  of  the  intense 
heat  and  light.  The  lavas  had  a  general  movement  to  the 
southwest.  "  A  large  stick  of  wood  thrown  on  the  lake,  at 
a  point  where  the  ebullition  produced  a  sort  of  eddy  or  roll- 
ing in  of  the  lava,  was  immediately  taken  out  of  sight ;  but 
the  next  instant  a  more  violent  ebullition  with  a  sudden  out- 


80  VOLCANIC   PHENOMENA 

burst  of  flame  and  smoke  told  how,  almost  instantaneously, 
the  stick  had  been  transformed  into  charcoal." 

In  July,  1847,  the  Great  Lake  was  boiling  in  much  the 
same  way  as  in  1846,  with  the  liquid  lavas  still  accessible,  so 
that  portions  were  taken  out  with  canes/ 

Dome  of  1848.  —  Early  in  1848  the  lake  was  the  most  of 
the  time  unusually  inactive,  and  became,  as  Mr.  Coan  states,'^ 
thickly  encrusted  over.  The  solid  crust  was  soon  after  raised 
into  a  dome  two  or  three  hundred  feet  high,  covering  the 
whole  lake.  By  August,  the  dome  was  almost  high  enough 
"  to  overtop  the  lower  part  of  the  outer  wall  of  Kilauea  and 
look  out  upon  the  surrounding  country."  The  fires  within 
were  visible  through  fissures ;  and  occasionally  lavas  were 
ejected  in  sluggish  masses,  or  forcibly,  from  several  apertures 
or  orifices  of  the  dome,  which  ''  rolled  in  heavy  and  irregular 
streams  down  the  sides,"  spreading  and  cooling  over  the  slopes 
or  at  the  base.  "  The  dome,  as  it  now  stands,"  Mr.  Coan 
wrote,  "  has  been  formed  by  the  compound  action  of  upheav- 
ing forces  from  beneath,  and  of  eruptions  from  the  openings 
forming  successive  layers  upon  its  external  surface." 

This  is  the  first  account  of  a  doiue  over  Halema'uma'u ; 
and  the  description  and  explanation  of  it  agree  essentially 
with  accounts  of  the  most  recent,  for  the  external  additions 
were  but  a  small  part  of  its  mass.  During  the  most  part  of 
the  year  1848  "no  fire  was  to  be  seen  in  Kilauea,  even  in 
the  nisht." 


*o 


Eruption,  probably,  of  1849.  Changes  from  1849  to 
18-35.  —  After  the  events  just  mentioned,  no  important  change 
in  the  crater  is  mentioned  before  the  spring  of  1849,  when  in 
April  and  May  there  was  a  return  to  great  activity,  and  start- 

1  Coan,  American  Journal  of  Science,  1851,  xii.  80,  letter  of  January,  1851.  The 
author  has  a  common  iron  spoon  containing  a  spoonful  of  lava,  dipped  up  by  Mr.  Coan 
at  one  of  his  visits.     It  is  striking  evidence  of  the  extreme  liquidity  of  the  lava. 

2  Ibid.,  p.  81. 


IN   THE   HISTORY   OF   IvILAUEA.  81 

ling  detonations  were  heard  from  the  cones  about  the  dome. 
The  lavas  were  projected  to  a  height  of  fifty  to  sixty  feet 
from  an  opening  in  the  top  of  the  dome,  and  moreover  the 
action  became  so  violent  elsewhere  that  ''  travellers  feared 
to  descend  into  any  part  of  the  crater."  This  state  of  "un- 
usual activity  was  such  as  foreboded  an  eruption.  It  sud- 
denly ceased,  and  probably  by  a  subterranean  discharge.  It 
left  the  central  plateau  and  the  dome  undisturbed  ;  but  the 
lavas  were  gone  from  Halema'uma'u  ;  only  escaping  vapors 
attested  to  fires  beneath. 

A  time  of  unusual  quiet,  of  '^  steaming  stupefaction,"  fol- 
lowed, and  continued  on  through  1850  and  1851.^  Early  in 
1852  the  orifice  at  the  top  of  the  dome  was  one  hundred  feet 
across,  and  boiling  lavas  were  seen  within.^  By  July  this  ori- 
fice had  increased  to  two  hundred  feet ;  and  it  was  still  en- 
larging by  falls  of  great  masses  into  the  abyss  one  hundred 
and  fifty  feet  below,  while  steam  and  smoke  were  escaping 
from  many  holes  in  the  sides  of  the  dome,  and  lavas  were 
ejected  through  a  fissure  dividing  tlie  west  wall  from  top  to 
bottom.  ^Elsewhere  the  interior  of  Kilauea  had  little  changed.^ 
Mr.  Coan  predicted  the  speedy  engulf ment  of  the  falling 
dome;  but  in  the  latter  part  of  1853  it  was  still  standing, 
and  probabl}'  was  two  miles  in  circuit,  with  a  height  of 
three  to  six  hundred  feet.^ 

The  great  central  plateau,  surrounded  by  what  used  to  be 
called  the  "  black  ledge,"  continued  rising,  and  in  1853  its 
surface,  by  Mr.  Coan's  estimate,  was  six  hundred  feet  above 
the  bottom  of   1840,  and  in    part  two  hundred   feet  above 

^  Coaii,  American  Journal  of  Science,  1852,  2d  series,  xiii.  397. 

*  Ibid.,  1852,  xiv.  219,  letter  of  March  5,  1852. 
3  Ibid.,  1863,  XV.  63,  letter  of  July  31,  1852. 

*  Ibid.,  1854,  xviii.  96,  letter  of  Jan.  30,  1854.  "The  Island  Worhl  (jf  the 
Pacific,"  by  Eev.  Henry  T.  Cbeever  (8vo,  New  York),  appeared  in  1851,  with  an 
account  of  a  visit  to  Kilauea.  But  the  descriptions  give  no  information  of  value, 
and  the  two  plates  relating  to  KiLauea  (pp.  287,  307)  are  from  Wilkes,  with  large 
modifications  in  one  and  no  acknowle<lgments  ;  and  witli  no  statements  tliat  the 
view  of  the  crater  is  an  1840  view,  not  1850. 

11 


82  VOLCANIC   PHENOMENA 

the  ledge.  His  letter  says  :  '"  Rising  is  going  on  .  .  .  first 
by  the  lifting  forces-  below,  .  .  .  second,  by  eruptive  overflow- 
ings ;  the  former  is  more  uniform  and  general,  the  latter 
irregular  and  partial ; "  the  former  "  in  some  places  grad- 
ually, in  others  abruptly."  Lyman's  ridge  of  lava-blocks 
still   existed,  little   changed. 

The  crater  continued  •'  unusually  dull "  through  1854. 
The  central  plateau  had  been  long  out  of  reach  of  the  fires, 
and  ferns  and  Ohelo  bushes  were  growing  on  it. 

Ekuption,  probably,  of  1855.  —  In  1855  a  change  to  un- 
usual activity  occurred,  and  it  is  thought  probable  that  an 
eruption  was  the  sequel.^  The  lavas  underneath  the  dome 
commenced  throwing  up  jets  to  a  height  of  two  hundred  feet ; 
vents  were  opened  over  the  surface  of  the  old  black  ledge  ;  and 
thus  in  May  and  June  the  great  central  plateau  had  a 
girdle  of  fires  nearly  half  a  mile  wide,  in  which  Mr.  Coan 
says  he  could  count  sixty  lakes  of  "  leaping  lavas."  There 
was  one  great  lake  at  the  foot  of  the  northeast  path  down 
into  the  crater,  and  other  "  boiling  caldrons  "  not  far  dis- 
tant, so  that  access  to  the  pit  was  cut  off.  The  crater 
seemed  to   be  ready  for  another  eruption. 

On  July  6  Mr.  Titus  Munson  Coan  was  at  the  crater,  and 
found  the  lava-lake  in  tlie  northeast  quarter  mostly  crusted 
over,  but  in  some  places  along  its  margin  the  lavas  were 
in  violent  action,  splashing  and  throwing  up  the  fiery  spray. 
Halema'uma'u  was  by  estimate  four  hundred  by  two  hundred 
and  fifty  feet  in  its  diameters,  and  seventy-five  feet  deep  to 
the  lava.  A  grayish  filmy  crust  of  hardened  lava  covered  it 
most  of  the  time.  But  every  four  or  five  minutes,  near  the 
centre,  the  crust  would  grow"  thinner,  split,  and,  rapidly 
parting,  open  to  view  a  fiery  surface  ten  to  eighteen  feet 
across,  in  wdiich  the  lava,  after   heaving   up  and  down  for 

1  Coan,  American  Jonrnal  of  Science,  1856,  xxi.  K>0,  letter  of  July  18,  1855,  and 
p.  139,  letter  of  Oct.  15,  1855. 


IN   THE   HISTORY   OF   KILAUEA.  83 

a  few  seconds,  burst  into  a  fountain  of  twenty  to  thirty 
feet ;  and  then,  falling  back,  the  spot  became  quiet  and  the 
red  surface  quickly  took  on  its  gray  filmy  covering.  Near 
by,  another  similar  fountain  in  a  few  seconds  would  start 
into  action  and  go  through  the  same  changes.  In  great 
cavern-like  openings  under  the  northeast  wall,  there  were 
furious  surgings  and  outt brows  of  the  lavas.  The  wall  of 
Halema'uma'u  was  tufted  with  Pele's  hair,  which  was  per- 
petually being  formed  from  the  lava  projected  into  the 
air.  Two  islands  stood  unmelted  in  the  northwest  part  of 
the  lake. 

On  October  9  the  crater  was  still  active,  but  less  intensely 
so.     The  dome  over  Halema'uma'u  had  fallen  in. 

Mr.  Coan's  report  of  March,  1856,  mentions  several  visits 
to  the  summit  eriqjtion  then  in  progress,  but  nothing  about 
Kilauea  until  October  of  that  year,  when  he  speaks  of  the 
crater^  as  declining  in  activity  for  the  year  past,  since  the 
sunnnit  eruption  began  ;  '•  getting  moi'e  and  more  profoundly 
asleep  ;  .  .  .  only  a  little  slug^n.sh  lava  in  the  great  pit  of 
Halema'uma'u,  but  much  escaping  vapor."  A  subterranean 
discharge  took  place  probably  in  October,  1855. 

1855  to  1864.  —  In  June  of  1857  Kilauea  was  still  quiet.^ 
The  lavas  of  the  Great  Lake  were  but  five  hundred  feet  across, 
and  one  bund  red  feet  below  the  edge.  The  alternations  from 
the  crusted  to  the  completely  molten  state  took  about  three 
ininutes. 

Through  the  following  year,  as  during  the  two  preceding, 
there  was  little  change.  In  August,  1858,  the  Great  Lake, 
some  five  hundred  feet  in  diameter,  "  boiled  and  sputtered 
lazily  at  the  centre  of  a  deep  basin  which  occupied  the 
locality  of  the  old  dome.  The  action  alternated  between 
general  refrigeration  and  a  breaking  up  of  the  whole  sur- 
face  with  intense   ebullition."  ^ 

^  Coaii,  American  Journal  of  Science,  1857,  xxiii.  4.35,  letter  of  Oct.  22,  1856. 

2  Ibid.,  1858,  XXV.  136,  letter  of  Sept.  1,  1857. 

3  Ibid,  1S59,  xxvii.  411,  letter  of  Feb.  3,  1859. 


84 


VOLCANIC   PHENOMENA 


In  180!^  the  condition  was  but  little  different.  Halema'u- 
ma'u  had  a  lake  at  centre  "'  about  six  hundred  feet  in 
diameter."  Within  the  basin,  a  fourth  of  a  mile  from  the 
border  of  the  lake  at  its  centre,  there  was  a  large  mound  of 
lava  (a  blow-hole  product),  with  pinnacles  and  turrets,  some- 
what cathedral-like.^  In  the  summer  of  1863  ^  activity  had 
not  much  increased  ;  at  intervals  of  a  few  seconds  to  half  a 
minute,  a  large  fountain  broke  forth  at  the  middle  of  the 
lake,  throwing  up  a  rounded  crest  of  lava  ten  to  twelve  feet. 


KILAUEA 
WM.  T.   BRIGHAM 


and  smaller   portions  to  a  height  of  twenty  to  thirty  feet, 
while   elsewhere    there    was   a    filmy    crust    through    which 


1  Coan,  American  Journal  of  Science,  1863,  xxxv.  29G,  letter  of  Nov.  13,  1862. 

2  0.  H.  Gulick,  Ibid.,  1864,  xxxvii.  416,  letter  of  July  25,  1863. 


IX   THE   HISTORY   OF   KILAUEA.  85 


small  stones  tlirowii  in  sank ;  and  then  again  there  was 
ebullition  at  various  points  in  the  lake,  —  facts  showing 
that  the   action  was  still  far  from   brilliant. 

In  October,  I860,  Mr.  Coan  reported  new  activity  in  the 
Great  Lake,  and  through  the  whole  circumference  of  the 
crater,  with  outHows  that  covered  the  old  black  ledge  with 
fresh  lavas.  But  the  central  plateau,  "  a  distinct  table-land," 
probably  five  to  six  hundred  feet  above  the  bottom  of  1840, 
remained  unchanjj-ed.^ 


'&" 


1864-1866.  Ohservations  and  Map  of  Me.  William 
T.  Beigham. — In  1864  Mr.  Brigham  visited  Hawaii,  and 
began  the  observations  on  its  volcanoes  reported  in  his 
memoir.  The  accompanying  reduced  copy  of  the  map 
made  by  him  from  his  survey  in  1865,  deserves  special 
attention.  The  map  confirms  the  statements,  made  from 
1846  onward,  as  to  the  obliteration  of  the  lower  pit.  It 
shows  the  southwestern  sulphur  banks,  but  much  dimin- 
ished in  extent  since  184(1  from  lava-overflows.  Halema'u- 
ma'u  has  apparently  its  old  position,  or  is  very  near  it. 
There  are  also,  on  the  map,  other  lakes  of  small  size ; 
cones,  two  or  three  of  which  were  driblet-cones,  of  blow-hole 
origin,  and  one,  e,  named 
the  Cathedral,  from  its  half- 
dozen  turrets  (here  repre- 
sented from  his  figure),  is 
the  same  that  Avas  seen  in 
1862   by  Mr.   Coan. 

The  map  shows  also  two 

.     .  The  Cathedral  .  Dkiblet-coxe,  1861. 

lung  pieces  (e/,  i  j)  of  Ly- 
man's ridge  of  loose  blocks   of  ''  compact  broken  lava,  .  .  . 
concentric."  as   Mr.  Brigham  reports,  "  with  the  main  wall 
of    Kilauea.  .  .  .  marking  the  limits    of  Dana's    black    ledge 
[that  is,  the  black  ledge  of  1840]  ;  .  .  .  composed  of  fragments 

^  ("oan,  American  Journal  of  Science,  1864,  xxxvii.  415,  letter  of  Oct.  G,  1SG3. 


86  VOLCANIC   PHENOMENA 

of  all  sizes  and  shapes,  very  solid  and  heavy;  and  full  of 
small   trrains   of   olivine." 

A  recent  letter  from  Mr.  Brigham  informs  the  Avriter  that 
the  ridge  ij  (which  is  not  particularly  mentioned  in  the  re- 
port) had  the  same  constitution  as  ef,  but  consisted  of  larger 
blocks. 

Other  interesting  features,  indicated  on  the  map,  are  (1)  a 
wall,  a  b,  —  fault-wall,  —  enclosing  an  amphitheatre,  that  of 
the  Halema'uma'u  region,  perhaps  a  result  of  the  undermin- 
ino;  occasioned  bv  a  discharge  of  the  lavas  of  the  lake  at  some 
unrecorded  time;  (2)  just  north  of  this,  a  deep  fissure,  c  d, 
concentric  with  the  wall  a  h ;  and  (3)  warm  or  hot  steaming 
caverns  in  the  floor  of  the  crater,  some  of  which  were  hung 
with  gray-black,  often  tubular,  stalactites.^ 

The  text  states  that  in  1864  the  "'  black  ledge  "  region  was 
fifty  feet  below  the  level  of  the  interior  plain  of  the  crater, 
and  that  the  difference  in  level  was  the  same  in  May,  1866, 
althouo-h  both  had  been  much  raised,  —  "  at  least  a  hundred 
feet,"  —  the  former  by  overflows  and  the  latter  without 
overflows. 

Mr.  Brigham  does  not  allude  to  Mr.  Lyman's  explanation 
of  the  long  ridge  of  lava-blocks.  He  remarks  as  follows  on 
page  421,  after  stating  the  constitution  of  the  ridge,  as  already 
cited :  "  This  wall,  which  is  concentric  with  the  main  wall 
of  Kilauea,  is  said  to  rise  and  fall  and  sometimes  disappear,  — 
which  seems  to  be  a  fact,  although  no  one  has  ever  seen  it 
in  motion.  It  is  [made  up  of]  the  fragments  broken  from 
the  edge  of  the  crater  by  an  eruption,  and  floated  out  to  its 
[the  wall's]  present  position."  Again  (p.  415):  "From  a 
manuscript  map  prepared  by  Mr.  Lyman,  I  find  the  ridge 
occupied  the  same  position  as  at  present."  Again,  in  his 
account  of  the  crater  in  May,  1866  (p.  427):  "The  ledge 
of  broken  lava  which  swept  aroimd  the  eastern  end  of  the 

^  The  stalactites  are  described  on  a  fullowing  page.    The  temiierature  of  the  caves 
wasusuanv80°-95°  F. 


IN   THE   HISTORY   OF  KILAUEA. 


87 


crater,  marking  the  limits  of  Dana's  black  ledge,  is  nearly 
covered  with  the  successive  overflows." 

The  Great  Lake  had  a  diameter  of  about  eight  hundred  feet 
in  1864,  and  of  one  thousand  in  August,  1865.  Its  lavas  in 
1864  were  fifty  feet  below  the  edge,  and  extended  into  cav- 
erns beneath  it.  The  action  was  mostly  feeble :  "  occasion- 
all}'  a  crack  opened,  and  violent  ebullition  commenced  at 
several  points ;  "  again  it  was  liquid,  but  soon  passed  to  the 
viscid  condition ;  again  "  boiling  violently,  and  dashing 
against  the  sides,  throwing  the  red-hot  spray  high  over  the 
banks."  There  were  two  small  islands  in  the  lake  in  1864  ; 
but  in  August,  1865,  they  had  disappeared,  and  the  lavas 
were  then  only  thirty  feet  below  the  edge. 

The  following  view  is  copied  from  a  photograph  of  a  paint- 
ing by  Mr.  Perry,  a  California  artist,  which  I  received  from 
Mr.  W.  T.  Bridiam  in  March,  1865 :  — 


,~^,',:;„:>   ,j—' 


S'Tt.V-'*    iCETS. 


KiLAUEA    IN    1864. 


Its  close  correctness  is  sustained  by  comparison  of  the  out- 
lines of  Kilauea  with  those  of  Drayton's  sketch.  It  has  great 
interest  because  it  gives  the  position  and  general  appearance 
of  Lyman's  ridge  of  lava-blocks,  corresponding  well  with  the 


88  VOLCANIC   PHENOMENA 

same  in  Mr.  Brigbam's  map.  The  point  from  which  the 
view  was  taken  was  apparently  a  little  to  the  east  of  that 
selected  by  Drayton,  and  hence  the  differences  in  the  western 
wall  and  some  other  points. 

The  existence  of  flames  over  the  large  boiling  lake  is  at- 
tested to  by  Mr.  Brigham,  who  says,  on  page  423,  speaking 
of  a  midnight  view,  that  "  they  burst  from  the  surface,  and 
were  in  tongues  or  wide  sheets  a  foot  long  and  of  a  bluish 
green  color,  quite  distinct  from  the  lava  even  where  white- 
hot.  They  played  over  the  whole  surface  at  intervals,  and  I 
thought  they  were  more  frequent  after  one  of  the  periodical 
risings  of  the  surface." 

In  May,  June,  and  July  of  1866  ^  there  was  a  great  increase 
of  activity  in  Kilauea,  beginning  just  after  the  cessation  of 
the  summit  eruption.  In  May  new  lakes  of  lire  and  new  cones 
were  opened  along  a  curving  line  extending  from  the  Great 
Lake  northwest  to  north  and  northeast,  thus  again  covering 
the  "  black  ledge  "  portion  of  the  crater,  flooding  the  surface 
with  lavas  for  a  distance  of  two  miles,  and  with  a  breadth  in 
some  places  of  half  a  mile ;  and  for  days  the  flood  of  lavas 
closed  the  usual  place  of  entrance  to  the  crater.  Large  blocks 
were  shaken  down  from  the  walls  of  Kilauea ;  and  Mr.  Brig- 
ham  observes  that  these  blocks  were  soon  removed  by  the  in- 
tensely active  flood  at  their  base,  ''  showing  how  pit  craters 
ma}'  be  enlarged  horizontally."  In  August  the  force  of  the 
eruption  seemed  to  be  spent ;  but  no  subterranean  outflow  is 
known  to  have  occurred.  During  all  the  activity  the  central 
plateau  of  the  crater  remained  undisturbed. 

Eruption  of  1868.  —  In  1868  a  great  outbreak  and 
down-plunge  took  place  in   Kilauea,   almost  simultaneously 

^  Coan,  American  Journal  of  Science,  1867,  2d  .series,  xliii.  264  ;  Brigham's 
Memoir,  p.  427. 


IX    THE   HISTOKY   OF   KILAUEA.  89 

with  iin  eruption  from  the  summit-crater  of  Mount  Loa.^  It 
was  preceded  by  a  succession  of  heavy  earthquakes.  —  two 
thousand  or  more,  according  to  reports,  —  commencing  on  the 
27th  of  March  and  cuhninating  on  Thursday,  tlie  2d  of  April, 
when  a  shock  occurred  of  terrific  violence,  which  was  de- 
structive through  the  districts  of  Hilo,  Puna,  and  Kau,  north- 
east, east,  south,  and  southwest  of  Mount  Loa,  and  was  felt 
far  west  of  the  limits  of  Hawaii.  With  the  occurrence  of 
this  great  shock,  fissures  were  opened  from  the  south  end  of 
Kilauea  soutliwestward  througli  Kapapala,  a  distance  of  thir- 
teen miles,  and  bending  thence  southward  toward  the  coast. 
The  position  of  this  line  of  lissures  is  shown  on  the  large 
map  of  Hawaii  published  by  the  Government  Survey  in  1887 
(frontispiece) ;  it  followed  the  course  of  the  earlier  fissures  of 
1823.  Some  lavas  were  ejected  from  the  openings  in  Kapa- 
pala, which  were  probaljly  lavas  from  Kihiuea.  Simultane- 
ously with  the  violent  shock,  a  decline  began  in  the  fires  of 
Kilauea.^  By  night  of  that  same  Thursday,  the  liquid  lavas 
had  disappeared  from  all  cones  and  were  confined  to  the 
lakes ;  by  Saturday  night,  all  the  lakes  were  emptied  except 
the  Great  Lake  ;  finally,  by  Sunday  night,  tlie  oth,  the  Great 
Lake  had  lost  its  lavas,  and  all  was  darkness  and  quiet. 
Where  the  lava  went  to  is  unknown. 

A  down-plunge  of  the  central  part  of  the  floor  of  the  crater 
took  place  at  the  same  time,  so  that  again  a  lower  pit  ex- 
isted, as  in  1840.  Mr.  Coan,  in  describing  it,  says  that  the 
plateau  "  sagged   down "   three  hundred   feet ;    and  another 

1  Dr.  William  Hillebrand,  American  Journal,  of  Science,  1 868,  2tl  series,  xlvi. 
p.  115  ;  Coan,  Ibid.,  p.  106  ;  F.  S.  Lyman,  Ibid,  p.  109;  H.  M.  Whitney,  Ibid., 
p.  112  ;  Coan,  Ibid.,  1869,  xlvii.  89,  letter  of  Sept.  1,  1868,  with  a  map  of  southern 
Hawaii  on  page  90.  Also  the  same  letters  in  a  paper  by  Mr.  "William  T.  Brigham, 
in  the  Memoirs  of  the  Boston  Society  of  Natural  History,  i.  o()4,  with  a  ma[)  on 
page  572.  The  map  was  made  by  Mr.  Brigham  from  liis  survey  in  1865  and  the 
descriptions  of  the  1868  eruption. 

2  A  letter  from  Rev.  E.  P.  Baker,  of  April  5,  1888,  states,  on  the  authority  of 
Mr.  Richardson,  that  the  subsiding  of  the  lavas  began  immediately  after  the  earth- 
quake of  April  2d. 

12 


90  VOLCANIC   PHENOMENA 

writer,  after  a  visit  to  the  pit,  gives  the  same  depth,  and  re- 
marks "just  as  ice  falls  wlien  the  water  is  drawn  from  be- 
neath." The  great  sunken  area  had  not  vertical  walls,  like 
that  of  1840,  but  sloping  sides,  as  the  term  ''  sagged  "  im- 
plies ;  the  slope  generally  thirty  to  sixty  degrees,  but  at  a 
much  less  angle  on  the  side  toward  Halema'uma'u.  There 
was  again  a  black  ledge,  and  it  was  nearly  of  its  old  width, 
but  at  a  somewhat  hig-her  level  owino;  to  the  overflows.  The 
emptied  Great  Lake,  three  thousand  feet  in  diameter  at  the 
top,  fifteen  hundred  feet  below,  and  five  hundred  feet  deep, 
was  literally  empty ;  it  showed  no  light  at  bottom  by  day 
and  not  much  at  night.  The  discharge  of  lava  may  have 
been  as  great  as  in  1840,  although  the  lower  pit  made  by  the 
undermining  had  less  extent. 

Mr.  Nordhoff,  in  his  "  Northern  California,  Oregon,  and 
the  Sandwich  Islands,"  ^  page  45,  says,  speaking  of  this  out- 
break :  "  Suddenly,  one  day,  the  greater  part  of  the  lava-floor 
sank  down,  or  fell  down,  a  deptli  of  about  five  hundred  feet, 
to  the  level  where  we  now  walked.  The  wonderful  tale  was 
plain  to  us  [March  o,  1873]  as  we  examined  the  details  on 
the  spot.  It  was  as  though  a  top-heavy  and  dried-out  pie- 
crust had  fallen  in  at  the  middle,  leaving  a  part  of  the  cir- 
cumference bent  down  but  clinging  at  the  outside  of  the 
dish."  Mr.  Nordhoff's  statement  as  to  the  deptli  of  the  lower 
pit  was  evidently  quoted,  and  is  not  independent  testimony ; 
but  his  comparison  suggested  by  the  sight  of  the  place,  suf- 
ficiently intelligible  to  an  American,  attests  to  the  reality  of 
the  subsidence. 

Another  remarkable  fact  is  stated  :  that  just  before  the 
earthquake  of  the  2d  of  April,  "  the  lavas  of  Kilauea  burst 
up  vertically  and  spread  over  the  old  deposit  of  1832."  A 
fissure  opened  in  the  depressed  area  between  Kilauea  and 
Kilauea-iki,  which  extended  on  for  nearly  a  hundred  yards. 

1  Nordhoff,  Northern  California,  etc.,  New  York  and  also  London,  1874. 


IN    THE    HISTORY   OF   KILAUEA.  91 

The  lava  of  the  outflow  was  still  lustrous,  and  mostly  free 
from  vegetation  in  the  summer  of  1887,  while  that  of  1832 
was  much  weathered  and  mostly  under  dense  vegetation. 
As  has  happened  in  most  Hawaiian 
eruptions,  trees  were  enveloped  by 
the  lava-flood.     Half-charred  trunks  J"' "  •"'■i\ 

were  standing,  in  1887,  with  a  rough  (^^^'''*"  '^ 

cylmdrical  encasement  of  lava  about  £>.  .       '  •(k 

the  stumps,  projecting  from  two  to       I^^^^B^:^^--' 
two  and  a  half  feet  or  more  above       !~^':t:;5^^SiM^a^A^*^ 
the  level  of  the  solidified  stream,  as 

in  the  figure,  showing  that  when  the  lava  reached  the  trees 
on  its  way  down  the  slope,  it  had  greater  height  of  surface 
than  afterward  when  the  flow  had  passed  by  and  its  final 
level  was  attained. 

On  Tuesday,  April  7th,  five  days  after  the  beginning  of 
the  Kilauea  discharge,  the  lavas  were  ejected  in  great  volume 
at  Kahuku  in  southwestern  Hawaii,  and  flowed  to  the  sea. 
It  was  at  first  a  question  whether  a  part  of  the  Kahuku  flow 
might  not  have  come  from  Kilauea.  But  the  extinction  of 
the  summit  fires  occurred  at  the  same  time,  and  the  Kaliuku 
discharge  was  in  a  line  with  fissures  leading  toward  it  from 
the  summit,  so  that  Mokuaweoweo  is  believed  to  have  been 
their  only  source.  Tlie  conduit  of  the  Kilauea  lavas  was 
probably  ruptured  at  the  time  of  the  great  shock,  and  lience 
the  discharge. 

The  curving  of  the  Kilauea  fissures  from  Kapapala  toward 
the  coast  seems  to  point  to  a  submarine  discharge  off  that 
part  of  the  island. 

4.   Kilauea  from  1868  to  1890. 

This  period  of  eighteen  years  passed  without  another 
down-plunge  of  the  floor  of  the  pit.  The  gradual  filling 
of    the    new-made    lower  pit,  and  the   ultimate  merging  of 


02  VOLCANIC   PHENOMENA 

all  sloDes  at  the  crater's  bottom  into  those  leading;  off  in 
all  directions  from  Halema'uma'ii,  are  the  chief  events  of 
the  period.  Mr.  Lydgate's  map,  on  the  following  page,  shows 
an  intermediate  stage  in  the  progress. 

Changes  from  18G8  to  1879. — After  the  discharge  and 
consequent  exhaustion  of  1868,  Kilauea  was  slow  in  its  re- 
turn to  activity.  In  July  of  1860  Mr.  Coan  found  the  crater 
quiet,  and  the  basin  of  the  Great  Lake  so  nearly  cooled  that 
he  went  down  into  it  and  measured  across  its  bottom  four 
hundred  feet  below  the  rim  ;  he  found  it  '*  five  sixths  of  a 
mile"  wide,  and  at  top  more  than  a  mile  froni  the  north  to 
the  south  side.  Down  deep  fissures  within  the  emptied  basin 
he  could  see  the  lavas,  fifty  to  one  hundred  feet  below,  still 
in  ebullition.^ 

Two  years  later,'-^  in  1871,  the  Great  Lake  was  full,  and 
successive  overflowings  had  covered  deeply  the  southern  end 
of  the  crater  and  sent  streams  two  miles  northward,  filling 
the  central  pit  to  a  depth  of  fifty  feet.  In  August  of  1871 
Halema'uma'u  was  again  a  deep  cavity,  hot  and  full  of  dense 
\"apors,^  but  before  August  of  1872  it  was  full  with  lavas 
and  often  overflowing;  into  the  o;reat  basin  of  1868. 

On  March  3,  187o,  Halema'uma'u,  according  to  Mr.  Nord- 
hoff.*  was  divided  between  two  lakes,  their  shorter  diameter 
about  five  hundred  feet ;  "  the  two  were  separated  by  a  low- 
lying  ledge  or  peninsula  of  lava  ;  each  was  red,  molten,  fiery  " 
within.  From  the  ''  north  bank  "  the  depth  of  the  pit  or 
basin  down  to  the  lavas  was  seen  to  be  about  eighty  feet,  and 
"  the  two  large  lakes  appeared  to  be  each  nearly  circular." 

In  January,  1874,  says  another  observer,  the  lower  pit  was 
still  much  below  the  ledge.     The  surface  of  the  Great  Lake 

^  Coan,  American  Journal  of  Science,  1879,  3d  series,  ii.  454,  letter  of  August 
30,  1871,  and  xviii.  227. 

2  Ibid.,  1871,  ii.  454. 

3  Ibid.,  1872,  iv.  407,  letter  of  August  27.  1872. 

*  Northern  California,  Oregon,  and  the  Sandwich  Islands,  1874. 


IN   THE   HISTORY  OF  KILAUEA. 


93 


was  thirty-five  to  forty  feet  below  the  edge  of  the  basin,  and 
"possibly"  five  hundred  feet  by  nearly  half  a  mile  in  its 
diameters,  but  divided  almost  in  two  by  a  low  bank  of  rock. 
Four  months  later,  on  the  4th  of  June,  the  cone  about  the 
Great  Lake  had  risen  much,  and  the  lake  was  divided 
through  into  two  oblong  lakes,  a  northern  and  southern,  in 
the  direction  of  the  longer  diameter  ;  it  lay  below  precipitous 
and  partly  overhanging  walls  that  were  eighty  feet  high. 
The  action  was  less  intense  than  in  January.  There  were 
active  cones  near  by.  One  hundred  yards  from  the  lake,  one 
typical  blowing-cone  -'of  beehive  shape,"  twelve  feet  high, 


about  forty  feet  deep  within,  and  having  walls  two  feet  thick, 
was  throwing  up  jets  and  clots  of  lava  through  holes  in  its 


94  VOLCANIC   PHENOMENA 

sides,  '"with  a  deafening  or  rather  stunning  roar"  and  sub- 
terranean rumblings  and  detonations.^ 

In  June  of  1874  a  map  of  the  crater  was  made  by  Mr. 
J.  M.  Lydgate.'^  It  has  great  interest,  since  it  shows  the 
central  depression  or  pit  of  1868  still  well  defined,  and  also 
the  subdivision  of  Halema'uma'u,  above  alluded  to. 

Early  in  October  of  1874,  according  to  Mr.  Coan,  "•  the 
great  central  depression  of  1868  had  been  filled  up  by  de- 
posits about  two  hundred  feet,"  and  the  region  around  the 
Great  South  Lake  had  become  a  truncated  elevation  nearly 
as  high  as  the  southern  brim  of  the  crater.^ 

In  December,  1874,  Mr.  J.  W.  Nichols,  of  the  British 
Transit  of  Venus  Expedition  of  1874,  was  at  Kilauea.  A 
brief  note  by  him  contains  the  following  facts :  ^  A  low  cone 
around  Halema'uma'u  about  seventy  feet  high  ;  diameters  of 
the  basin  one-half  and  one-quarter  of  a  mile ;  within  it,  four 
lava-lakes,  the  largest  two  hundred  yards  in  length  ;  in  the 
largest,  seven  or  eight  fountains  of  white-hot  lava  playing  to 
a  height  of  thirty  to  forty  feet,  one  of  them  sometimes  stop- 
ping, and  then  connnencing  in  another  part  of  the  lake ;  the 
fountains  in  every  case  playing  around  the  edges  of  the  lake ; 
lava  of  largest  lake  about  fifty  feet  below  the  brim ;  one  of 
the  smaller  lakes  brimful  of  lava  when  in  the  others  the 
lava-surface  was  thirty  or  forty  feet  below  the  brim ;  in  one, 
a  single  fountain  bursting  from  a  cavern  in  its  side.  The 
summit  crater  is  stated  to  have  been  in  action  about  a  month 
before  the  visit. 

During  the  Year  1878  and  the  early  Part  of  1879. — In 
January,  1878,  Mr.  C.  J.  Lyons,  of  the  Government  Survey 

1  Isabella  L.  Bird,  The  Hawaiian  Archipelago,  Louduii,  1875,  pp.  55,  253. 

2  For  this  tracing  I  am  indebted  to  the  Surveyor-General,  Mr.  Alexander,  the 
original  being  in  the  archives  of  the  office  of  the  Hawaiian  Survey.  The  precise 
date  was  not  given  on  the  tracing  ;  but  by  letter  from  Mr.  Lydgate,  the  date  is 
now  known  to  be  as  given  above. 

^  Coan,  American  Journal  of  Science,  1874,  3d  series,  viii.,  letter  of  Oct.  6,  1874. 
*  Proceedings  oi' the  Edinburgh  Royal  Society  for  1875-1876,  ])p.  113-117. 


IN   THE   HISTORY   OF   KILAUEA.  95 

Office,  obtained,  by  means  of  a  theodolite,  three  hundred  and 
twenty-five  feet  as  the  level  of  the  lavas  of  Halema'uma'u 
below  the  datum  mark  at  the  Volcano  House. 

The  following  facts,  bearing  on  the  condition  of  the  crater 
in  1878  and  the  early  part  of  1879,  were  copied  by  the  author 
in  1887  from  the  hotel-book  of  the  volcano  :  — 

July  20,  1878.  "  Halema'uma'u  in  a  most  active  state."  —  M.  P, 
Robinson. 

September  20.     '•  Very  active."  —  J.  Mott  Smith. 

November  24.     "•  Very  active  ;  lava  within  a  foot  of  top  of  bank." 

Jan.  8,  1879.  '•  South  Lake  with  lava  fifty  feet  below  the  rim 
and  .boiling  like  water."  —  Wm.  Gardner. 

Marcli  19.     "  Large  and  bright  lake." 

April  15.     "  Light  wonderful." 

Eruption  of  1879.  —  The  facts  from  the  Volcano  House 
hotel-book  and  the  testimon}-  of  Mr.  Coan  and  others,  were 
evidence  that  Kilauea  was  ready  for  another  eruption.  The 
threatened  eruption  took  place  between  the  18tli  and  21st  of 
April,  1879,  —  the  21st,  according  to  information  reported  by 
Miss  C.  F.  Gordon  Cummings,  who  was  at  the  crater  in  the 
autumn  of  that  year.^  Mr.  Coan  reported,  in  a  letter  of  June 
20,  that  the  Great  Lake,  which  had  been  running  over,  and 
whose  rim  had  been  raised  till  nearly  as  high  as  the  outer 
edge  of  Kilauea,  was  suddenly  emptied  by  a  subterranean 
outlet  and  subsided  several  hundred  feet,  leaving  nothing  but 
"  a  smoking;  basin."  ^ 

But  the  hotel-book  records  fix  the  date  :  — 

April  21,  1879.  "  Bottom  dropped  out  of  crater."  —  Wm.  H. 
Lentz,  of  Honolulu. 

April  23.     "Found  tbe thing  extinct."  —  G.  Grceper. 

April  28.  "  Almost  extinct ;  some  vapors."  —  Rev.  K.  0.  Forbes, 
of  Honolulu. 

April  29.     "  No  fire  at  all.  .  .  .  Lake  quite  empty."  —  J.  Day. 

*  Fire  Fountains  of  the  Kingdom  of  Hawaii,  2  vols.  8vo,  London,  1883. 

-  Coan,  American  Journal  of  Science,  1879,  xviii.  227,  letter  of  June  20,  1879. 


96  VOLCANIC   PHENOMENA 

After  some  days,  in  which  there  was  no  evidence  of  fires 
except  that  from  escaj)ing  vapors  and  steam,  the  lava  re- 
appeared. The  hotel-book  of  the  Volcano  House  contains 
the  following  proof  that  in  June  the  great  basin  had  recov- 
ered activity  :  — 

June  24,  1879.  "  Throwing  up  jets  of  lava  ;  both  lakes  active  ; 
looks  like  a  fountain  of  fire  from  the  veranda  of  the  Volcano 
House."  —  Wm.  H.  Lentz. 

July  2.  "All  traces  of  two  lakes  of  July,  1878,  obliterated,  and 
instead  an  enormous  single  lake,  which  was  quite  active ;  .  .  .  lava 
thrown  up  fifty  feet."  —  Wm.  Tregloan,  of  Honolulu. 

By  May,  1880,^  Halema'uma'u  had  become  a  boiling  and 
overflowing  lake,  pouring  its  streams  into  the  great  central 
basin  of  the  crater. 

In  July  of  1880  Mr.  William  T.  Brigham  was  again  at  the 
crater.^  The  floor  was  found  to  rise  into  a  "  tolerably  regu- 
lar dome "  which  was  "  surmounted  by  four  lakes  of  an 
average  diameter  of  a  thousand  feet."  The  latest  of  the 
four,  the  southeastern,  commenced  to  form  May  15  of  that 
year,  and  its  bank  was  in  part  nearly  on  a  level  with 
the  lavas  ;  but  the  others  had  stratified  walls,  as  is  stated 
and  figured,  which  were  in  places  one  hundred  feet  or  more 
in  height,  and  from  their  front  there  were  frequent  avalanches, 
owing  to  the  undermining  action  of  the  active  lavas  beneath. 
These  lavas  were  seen  here  and  there  to  be  white  hot  in  the 
night  view.  In  the  darkness  "  a  large  volume  of  gas  "  was 
observed  escaping  from  a  cluster  of  blow-holes  in  the  vicinity 
of  the  lakes,  "  which  burned  with  a  bluish-green  flame,"  dif- 
fering in  its  continuance  from  the  flames  seen  before  by  Mr. 
Brio-ham,  which  "seldom  lasted  lono-er  than  a  few  moments." 

The  four  lakes  replaced  old  Halema'uma'u.  By  sighting 
from  two  of  his  monuments  left  from  the  1865  survey,  Mr. 

^  Coaii,  American  Joui-nal  of  Science,  1880,  xx.  V2,  letter  dated  May  3-C,  1880. 
2  Brigham,  Ibid.,  1887,  xxxiv.  19. 


IN   THE   HISTORY   OF   KILAUEA.  97 

Brigham  obtained  evidence  that  the  area  of  the  old  lake  lay 
"  in  the  midst  of  the  present  four  lakes  "  instead  of  corre- 
sponding with  either  of  them.  This  would  make  the  summit 
of  the  dome  to  be  in  the  Halema'mna'u  part  of  the  crater,  or 
its  southern  portion,  as  in  1886,  the  dome  having  in  fact  ^'  a 
very  eccentric  apex." 

In  1882  Captain  Button  made  his  examination  of  Kilauea. 
He  states  that  after  reaching  the  floor  of  the  crater  he  walked 
over  the  uneven  surface  for  about  a  mile  and  three-quarters, 
and  then  came  to  a  rapidly  ascending  slope,  rising  about  one 
hundred  feet ;  and  from  the  top  of  it  looked  down  on  "  New 
Lake,"  about  four  hundred  and  eighty  feet  long  and  three 
hundred  feet  in  width,  lying  between  walls  fifteen  to  twenty 
feet  liigh,  situated  to  the  northwest  of  Halema'uma'u.  This 
lake  first  appeared,  he  states,  in  May,  1881.^ 

New  Lake  was  much  of  the  time  crusted  over,  showing 
fires  only  at  the  edges.  Break-ups,  making  cracks'  over  the 
whole  surface,  and  followed  by  an  engulfing  of  the  number- 
less fragments  until  "  the  whole  was  one  glowing  mass  of 
lava,"  occurred  at  intervals  of  forty  minutes  to  two  and  a 
quarter  hours ;  but  they  were  of  short  duration,  and  the 
lavas  in  the  mean  time  were  ^'  quite  black  and  still."  Now 
and  then  a  fountain  broke  out  in  the  middle  of  the  lake  and 
boiled  feebly  for  a  few  minutes  ;  then  it  became  quiet,  "  but 
only  to  renew  the  operation  at  some  other  point."  The 
larger  and  more  active  lake,  Halema'uma'u,  half  a  mile  off, 
was  siuTOunded  by  a  cone  of  loose  lava-fragments,  the  lavas 
a  hundred  feet  below  the  top.  The  lake  was  to  a  consider- 
able extent  crusted  over  ;  but  there  were  boiling  fountains 
of  liquid  lava  five  to  ten  feet  high  (by  estimate)  in  play, 
changing  their  positions  from  one  part  of  the  lake  to  another, 
one  dying  out  as  another  started  up.     Two  masses  of  solid 

^  Coan,  American  Journal  of  Science,  1883,  xxv.  220,  letter  of  Feb.  8,  1883; 
and  United  States  Geological  Report,  loc.  cit. 

13 


98  VOLCANIC   PHENOMENA 

lava  were  seen  in  the  New  Lake,  looking  as  if  formed  in  it, 
whicli  in  the  course  of  several  days  shifted  their  positions, 
showing  that  they  were  floating  islands. 

Eruptio?^  of  March,  1886.  —  The  above-described  condi- 
tions continued,  though  with  great  variations,  until  March  of 
1886.  On  the  6th  of  that  month  both  Halema'uma'u  and 
the  "  New  Lake  "  (see  Plate  III.),  the  latter  five  3'ears  old, 
were  unusually  full  and  active,  and  mingled  their  floods  in 
overflows.  The  next  morning,  March  7,  between  two  and 
three  o'clock,  the  lavas  disappeared  and  left  both  basins 
empty,  — first  the  shallower  New  Lake,  and  then  the  Great 
Lake.  The  cone  around  the  latter,  then  two  hundred  feet  in 
height  above  the  boiling  surface,  fell  into  the  emptied  basin, 
and  for  days  the  down-plunge  of  the  walls  continued. 

The  eruption  was  thus  a  simple  running  off  somewhere  of 
the  lavas,  and  a  down-plunge  of  the  undermined  region  was 
a  consequence.  There  had  been  a  great  increase  of  activity 
within  and  about  Halema'uma'u,  whicli  at  last  had  extended 
in  a  subterranean  way  to  the  northern  borders  of  the  crater. 
The  fissures  of  the  solfatara  region  on  the  northern  border 
of  Kilauea,  west  of  the  Volcano  House,  sent  up  hotter  air 
and  vapors  than  usual,  foreboding  some  change.  The  bath- 
ing-house of  the  hotel,  fitted  up  for  vapor  baths,  is  in  this  de- 
pressed region  over  one  of  the  fissures.  The  proprietor  of 
the  house,  Mr.  J.  H.  Maby,  found  on  the  afternoon  of  the 
6 til  of  March  (Saturday),  when  wishing  to  take  a  bath, 
the  vapors  at  repeated  visits  too  hot  for  it,  and  finally  gave 
it  up.  At  half-past  nine  of  that  evening  a  slight  earthquake 
was  felt,  and  at  a  quarter  of  ten  three  others,  which  made 
''  thud-like  sounds,"  or  "  like  the  fall  of  a  meal-bag  on  the 
floor;"  at  ten  the  light  over  Halema'uma'u,  before  very 
brilliant,  suddenly  disappeared,  —  the  erwption  had  taken 
place. 

Through  Sunday  morning  the  escape  of  vapors  from  the 


Plate  H; 


The  Crater  or 

KI  LAI  IE  A 

UAyVAU . 


IN   THE   HISTORY   OF    KILAUEA.  99 

fissures  of  the  solfatara  region  near  the  A^olcano  House  went 
on,  but  it  ceased  entirely  on  Tuesday,  and  tlie  stoppage  con- 
tinued through  Wednesday  and  Thursday.  Afterward  the 
discharge  was  gradually  resumed. 

Forty-one  earthquakes  are  reported  as  having  occurred 
during  the  night,  but  none  strong  enough  to  shake  down 
furniture  in  the  Volcano  House,  or  crockery  from  shelves. 
The  shocks  have  been  attributed  to  the  down-plungings  of 
the  walls  of  Halenia'uma'u  consequent  on  the  discharge 
of  the  lavas  ;  but  the  intervening  distance,  twelve  thou- 
sand feet,  is  too  great  for  such  an  effect  from  the  feeble 
vibrations  so  caused.  Moreover,  there  was  a  cause  nearer 
by ;  for  deep  fissures  were  opened  for  a  mile  along  the  road 
that  goes  east  from  the  Volcano  House,  commencing  at  a 
point  not  far  from  the  house.  The  fissures  were  still  steam- 
ing in  August,  1887. 

The  forty-one  feeble  earthquakes  felt  on  the  margin  of  the 
crater  at  the  Volcano  House  disturbed  no  other  part  of  the 
island,  and  they  were  the  only  semblance  of  violence  at 
the  time  of  the  eruption.  There  was  a  down-plunge  as  in 
other  eruptions,  but  it  was  all  confined  within  the  area 
which  included  Halema'uma'u  and  the  associated  New  Lake. 

Where  the  lavas  of  the  lake  went,  is  the  old  question 
again  unanswered.  Perhaps  into  souie  cavernous  subter- 
ranean region,  or  perhaps  into  the  sea  by  an  opened 
fissure. 

The  New  Lake  had  had  since  1882  its  ''  floatino;  island." 
A  photograph  gives  the  following  view  of  it  in  its  earlier 
condition.  It  looks 
as  if  it  had  been  a 
part  of  a  solidified 
lava-stream  which 
had  been  floated  off 

from  the  sides  of  the  lake  or  had  been  buoyed  up  to  the  sur- 
face from  the  bottom.     Its  lavas  were  not  much  vesiculated  ; 


100 


VOLCANIC  PHENOMENA 


but  the  air-cells  were  evidently  sufficient  to  enable  it  to 
float.  It  changed  much  in  form  from  1882  to  1886,  as 
photographs  indicate,  probably  from  encroachments  on  it 
by  the  fusion  of  its  sides,  and  also  from  the  additions  to 
it  through  the  throws  of  liquid  lavas  over  it.  At  the 
eruption  it  was  left  stranded  at  the  bottom  of  the  emptied 


"Floating  Island"  of  New  Lake,  Stranded. 

lake-basin.  This  view,  exhibiting  its  condition  in  August, 
1887,  is  from  a  photograph.  It  is  not  known  how  much 
of  it  was  beneath  the  surface  of  the  lava  ;  but  the  reader 
may  perhaps  satisfy  himself  on  this  point. 

Aftei'  the  Eruption  of  March,  1886,  durimj  the  rest  of  the 
Year. — The  reports  of  Mr.  J.  S.  Emerson,  Prof.  S.  S.  Van 
Slyke,  and  Mr.  Dodge  give  details  as  to  the  conditions  of  the 
crater  within  the  first  eight  months  after  the  eruption.^  The 
first  and  last  were  made  to  the  Surveyor-General,  Professor 
Alexander. 

Mr.  Emerson  was  at  the  crater  seventeen  days  after  the 
event  on  March  24,  and  remained  till  April  14.  He  says 
that  in  this  interval  '•'  no  molten  lava  was  anywhere  visible 
in  the  entire  crater.  At  certain  points  of  easy  access  a  stick 
could  be  lighted  by  thrusting  it  down  a  crack  so  as  to  bring 

1  American  Journal  of  Science,  1877,  xxxiii.  87,  95,  98. 


IN  THE   HISTORY  OF  KILAUEA.  101 

it  in  contact  with  the  red-hot  rocks  beneath ;  but  in  general 
there  was  scarcely  a  place  from  which  I  was  prevented  access 
on  account  of  the  heat."  The  total  depth  below  the  datum 
at  the  Volcano  House  to  the  bottom  of  the  basin  of  Halo- 
ma' uma'u  was  found  to  be  nine  hundred  feet,  and  below  the 
rim  of  the  basin  about  five  hundred  and  ninety  feet. 

On  the  29th  of  March  he  descended  into  the  pit ;  only  Rev. 
E.  P.  Baker  had  preceded  him.  The  sides  were  covered,  not 
by  small  fragments  of  lava  or  gravel  or  scoria,  but  by  great 
irregular  slabs  of  the  smooth-surfaced  lava  (pahoehoe),  six  to 
eight  or  more  feet  long,  five  or  six  feet  wide,  and  about  a  foot 
thick,  and  mostly  so  placed  as  to  slope  downward,  though 
many  were  tilted  in  all  directions ;  they  looked  as  if  ready 
to  slip  to  the  bottom.  But  at  a  depth  of  about  three  hun- 
dred and  twenty-five  feet,  or  two  hundred  and  seventy- 
five  feet  from  the  bottom,  where  the  diameter  was  about 
six  hundred  feet,  this  rough  flooring  of  pahoehoe  slabs  came 
abruptly  to  an  end,  and  a  nearly  circular  pit  began,  which 
had  the  form  nearly  of  an  inverted  cone.  A  view  of  the 
condition  is  shown  in  the  accompanying  map  of  the  Hale- 
ma' uma'u  region  by  Mr.  Emerson.  The  lower  basin  had  an 
even,  lustreless  surface,  free  from  large  blocks  and  notable 
fissures,  and  consisted  chiefly  of  coarse  gravel  or  fragments 
of  lava,  but  at  bottom  of  smooth  black  pahoehoe,  free  from 
debris,  and  of  somewhat  triangular  shape,  with  sides  of 
twenty-five  feet.  From  a  small  fissure  issued  a  faintly 
bluish  vapor. 

In  the  upper  part  of  the  basin,  on  the  northwest  side, 
about  364  feet  above  the  bottom  and  225  feet  below  the  top, 
there  was  a  continuous  jet  of  steam  from  an  oval  aperture  of 
five  to  ten  feet.  This  continued  to  increase,  and  on  the  12th 
of  April  deposits  of  sulphur  were  formed  about  it. 

Within  the  basins  of  New  Lake  and  Little  Beggar 
there  were  hillocks  of  smooth-fissured  lava,  without  debris. 
The  huge   hulk  of    the  "  Floating    Island  "   lay  as    in    the 


102 


VOLCANIC   PHENOMENA 


sketch,  and  on  measurement  proved  to  be  sixty  feet  high  and 
fully  a  hundred  feet  in  length.  The  walls  of  the  emptied 
basin  of  New  Lake  were  for  the  most  part  nearly  vertical,  and 
were  everywhere  covered  with  a  black,  vitreous  enamel. 

The  hottest  part  of  the  Halema'uma'u  depression  was  on 
the  southwest  side ;  and  in  the  same  direction,  to  the  south- 


^  N  ^  \  xN 


~A^&  bono 


iM. 


\v;^ 


s?r^.;-^^V^''/n'i,ij:.:..^^^^ 


s^^^^^^SSliilS* 


IIai.ema'cma'u  in  April,  1886. 

west  of  Kilauea,  where  there  are  old  fissures  of  1868  which 
are  still  steaming,  there  were  other  fissures  which  appeared 
to  be  of  recent  origin. 

Professor  Van  Slyke  reached  the  crater  on  the  19th  of 
July,  —  three  months  after  Mr.  Emerson  left  it.  He  re- 
ported great  changes  in  Halema'uma'u  ;  for  liquid  lava  had 
again  appeared,  and  besides,  the  central  region  of  the  great 
basin  had  been  "  upheaved."  The  upheaving  will  be  under- 
stood from  Plate  III.     Within  the  basin  of  Halema'uma'u, 


_  w 


"^'ft^lif-itj 


IN   THE   HISTORY   OF   KILAUEA.  105 

/rom  four  hundred  to  a  thousand  feet  from  its  precipitous 
north  wall,  there  was  a  steep  mound  or  cone  of  loose  blocks 
of  solid  lava  about  a  hundred  and  fifty  feet  high,  dropping 
to  about  thirty  feet  on  the  northwest  side.  It  occupied  the 
central  part  of  tlie  basin,  and  consequently  had  a  deep  and 
wide  depression  around  it.  Already  a  lava-lake  of  about  five 
acres  existed  within  this  depression  ;  and  besides  this  Pro- 
fessor Van  Slyke  saw  active  fires  under  cover  beneath  the 
cone.     He  states  :  — 

"  Ascending  the  cone  part  way,  I  came  to  the  edge  of  a  deep  hole 
or  well,  of  rather  irregular  outline,  four-sided,  perhaps  thirty  or  forty 
feet  wide,  and  from  sixty  to  seventy -five  feet  long,  and  not  less  than 
a  hundred  feet  deep.  The  mouth  was  surrounded  by  masses  of  loose 
rocks,  rendering  approach  to  the  edge  impossible  or  very  dangerous, 
except  at  one  point ;  from  this  point  I  could  see  the  bottom  of  the 
well,  and  that  it  was  covered  with  hardened  fresh  pahoehoe.  At  one 
side  the  liquid  lava  could  be  seen  as  it  was  puffed  out  of  a  small  hole 
every  few  seconds  and  thrown  up  a  few  feet.  The  puliling  noise 
accompanying  the  ejection  of  the  lava  was  quite  like  that  of  a  rail- 
way locomotive,  though  louder.  The  a])erture  through  which  the 
lava  was  thrown  out  might  have  been  three  feet  long  and  two  feet 
wide.  Immediately  beneath  the  point  where  I  was  standing  there 
seemed  to  be  a  constant  and  tremendous  commotion,  attended  by  a 
peculiar  swashing  noise,  but  I  could  not  lean  sufficiently  far  over  with 
safety  to  see  anything.  Fumes  of  sulphur  dioxide  were  coming  up 
in  abundance,  but  being  on  the  windward  side  I  was  not  greatly 
annoyed  by  them." 

From  the  southeastern  side  of  Haleraa'uma'u  he  went 
again  up  the  sides  of  the  cone :  — 

"  This  led  to  a  second  well  or  deep  hole,  where  molten  lava  was 
visible.  This  well  was  nearly  round,  with  a  diameter  of  perhaps 
twenty  or  thirty  feet,  and  a  depth  of  about  a  hundred  feet.  At  one 
point  the  edge  could  be  safely  approached  ;  but  as  it  was  on  the  lee- 
ward side  the  fumes  of  sulphur  dioxide  could  be  endured  only  for  a 
few  seconds  at  a  time.  Like  the  other  well,  the  sides  were  perpen- 
dicular. At  the  bottom  was  a  cone  having  an  opening  at  the  top 
perhaps  ten  feet  across ;  and  inside  liquid  lava  was  boiling  with 
intense  violence,  every  few  seconds  throwing  up  a  jet  of  lava,  the 

14 


106  VOLCANIC   PHENOMENA 

spray  of  which  came  to  tlie  mouth  of  the  well  almost  into  my  face. 
The  drops  of  lava  thrown  to  the  mouth  of  the  well  liad  cooled  enough 
to  become  hardened  and  black  when  they  reached  the  level  on  which 
I  was  standing.  This  place  was  quite  noisy,  the  noise  resembling 
that  of  violently  swashing  waters." 

Besides  the  deep  holes  just  descril^ed.  there  was,  as  has 
been  mentioned,  a  "lake"  of  liquid  lava.  It  was  situated 
immediately  beneath  the  west  wall  of  Halema'uma'u  at  the 
bottom  of  the  wide  depression  between  this  wall  and  the 
cone-like  hill  of  loose  rocks.  It  extended  to  the  "  Smoke 
Jet,"  a  distance  of  four  hundred  feet  approximately.  It  was 
possible  to  get  down  to  the  edge  of  the  lake,  but  very  haz- 
ardous. On  the  occasion  of  his  first  visit,  in  a  view  from 
the  north  side,  the  entire  surface  was  hardened  and  black, 
the  only  sign  of  volcanic  activity  being  little  steam-jets  here 
and  there.  After  about  an  hour  some  liquid  lava  burst 
through  the  black  crust  and  flowed  awa}'.  Such  little  out- 
bursts were  followed  by  others  larger.  Two  days  later  there 
was  much  pufhng  and  swashing  and  some  boiling  lava. 

Mr.  Dodge  was  at  Kilauea,  on  survey  duty,  during  the  last 
week  of  the  following  September  and  the  first  of  October. 
The  map  (Plate  III.)  is  the  result  of  his  work  and  of  the 
previous  survey  of  Mr.  Emerson.  It  brings  out  strongly 
the  fact  that  previous  to  the  eruption  of  1886  the  floor  of 
the  crater  had  been  flooded  again  and  again  by  the  streams 
from  Halema'uma'u,  until  the  whole  was  covered  through- 
out with  the  new  lavas.  The  surface  sloped  away  from 
the  lake  in  all  directions,  as  it  had  done  since  1880,  and  this 
was  true  even  to  the  farthest  northeastern  walls.  These 
universal  fiery  floods,  making  the  existing  floor,  took  place 
during  1885,  or  the  year  preceding  the  eruption.  They  left 
the  depth  at  the  foot  of  the  northeast  wall  482  feet  below  the 
Volcano  House ;  over  the  centre  of  the  floor  350  to  375  feet, 
and  at  the  summit  of  the  eccentric  cone  of  the  crater,  about 
Halema'uma'u,  320  to  340  feet.     There  was  consequentl}^,  as 


P7-      g 


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«  2 


IN   THE   HISTORY   OF   KILAUEA.  109 

Mr.  Dodge  remarks,  a  slope  of  163  feet  to  the  northeast 
wall,  125  feet  to  the  northward,  below  Kamohoalii,  105  to 
the  middle  of  the  northwest  side,  below  Uwekahuna,  and 
about  eighty  feet  along  the  short  radius  to  the  southeastward. 
The  flow  had  also  encroached  upon  the  south  bluffs  of 
Kilauea,  and  covered  the  older  formation  at  the  head  of  the 
bay  near  Holoholokolea,  so  that  at  the  extreme  south  angle 
in  the  bluffs  a  further  rise  of  forty  feet,  more  or  less, 
would  cause  Kilauea  to   outflow  toward  the  sea. 

Mr.  Dodge  also  mapped  and  measured  the  debris-cone 
of  Halema'uma'u,  which  Professor  Van  Slyke  had  found 
already  ''  upheaved  "  in  Halema'uma'u,  and  determined  the 
height  of  some  of  its  summits  as  given  on  the  map.  The 
cone  he  found  to  have  a  breadth  from  northeast  to  south- 
west, of  1,080  feet,  from  east  to  west  of  1,100  feet,  from  north- 
west to  southeast  of  930  feet.  Consequently,  as  the  width 
of  the  Halema'uma'u  basin  from  east  to  west  was  2,300 
feet,  the  depression  or  trough  around  the  base  of  the  cone 
was  500  to  700  feet  on  either  side.  The  highest  point  in 
the  cone  scarcely  rose  above  the  level  of  the  margin  of  the 
Halema'uma'u  basin. 

The  basin  around  it  was  becoming  gradually  filled  by 
small  outflows  of  lavas  discharged  from  vents  opened  over 
its  floor,  especially  near  the  base  of  the  cone,  and  near  the 
wall,  where  were  many  small  cones  and  blowholes.  But 
outside  of  Halema'uma'u,  evidences  of  much  heat  were  con- 
fined to  three  or  four  places. 

Further,  Mr.  Dodge  obtained  evidence  that  the  floor  of 
the  basin  with  the  cone  upon  it  w^as  rising  bodily  ;  and  his 
observations  made  on  his  arrival  and  before  he  left  indi- 
cated that  the  elevation  was  going  on  "  at  the  rate  of 
nearly  a  foot  a  day."  This  he  further  confirmed  by  later 
observations  ;  and  on  the  14th  of  January,  1887,  wrote  that 
"  it  was  all  rising  slowly  as  though  floating  on  the  surface 
of  the  new  lava-lake;"  and  that  the  height  gained  thereby 


110  VOLCANIC   PHENOMENA 

above  the  sea-level  since  October  was  probably  two  hundred 
feet. 

The  material  of  the  cone  he  describes  as  coarse  angular 
debris,  with  finer  fragments,  the  same  that  Mr.  Emerson 
found  to  be  the  lining  of  the  basin.  The  structure  of  the 
north  end  —  and  the  rest  was  all  similar  —  is  well  shown  in 
Plate  IV.,  from  a  photograph  taken  in  January,  1887,  look- 
ing westward.  The  steaming  depression  at  its  base  is  part 
of  the  Halema'uma'u  basin.  The  stratified  wall  beyond  is 
the  west  wall  of  Halema'uma'u  ;  and  that  above,  also  strati- 
fied, is  the  west  side  of  Kilauea.  Above  this  faintly  in  the 
distance  is  the  dome  of  Mount  Loa,  covered  with  January 
snows. 

The  interior  of  the  cone  was  inaccessible  on  account  of  the 
vapors ;  but  from  the  flashes  of  light  seen  over  it  at  night, 
Mr.  Dodge  inferred  that  there  was  some  action.  His  native 
guide  said  to  him,  ''  Plenty  fire." 

In  various  places  over  the  exterior,  as  when  seen  by  Mr. 
Van  Slyke,  there  were  ''  openings  emitting  dense  bluish- 
white  vapors  under  considerable  pressure,  the  mouths  of 
which  were  coated  with  deposits  of  sulphur  and  at  night 
in  some  cases  glowed  with  red  heat." 

Plate  V.  shows  the  condition  in  October.  The  photo- 
graph, of  which  it  is  a  copy,  was  taken  on  a  cloudy  day, 
and  hence  the  structure  of  the  cone  is  not  distinct ;  but  the 
steaming  apertures  are  nearly  as  described  by  Mr.  Van  Slyke. 
The  surface  in  the  foregroimd  is  that  of  the  Halema'uma'u 
basin  on  the  northeast  side  ;  and  the  walls  beyond  are,  as  be- 
fore, those  of  the  Halema'uma'u  basin  and  of  Kilauea,  —  the 
former  one  hundred  to  one  hundred  and  fifty  feet  in  height. 

Plate  VI.  represents  the  cone  six  or  seven  months  later, 
in  the  spring  of  1887.  Progress  had  been  made  of  a  kind 
that  threatened  the  life  of  the  cone  ;  for  the  steaming 
apertures  in  its  side  had  become  steaming  vents  of  consider- 
able length,  too  copious  in  vapors  to  admit  of  approach. 


5"  2; 


-    g 


^    g 


IN   THE  HISTORY  OF  KILAUEA.  113 

Three  or  four  months  later,  in  August,  1887,  at  the  time 
of  the  author's  visit,  the  Halema'uma'u  cone,  as  seen  from 
the  Volcano  House,  nearly  three  miles  distant,  had  the  ap- 
pearance shown  in  the  following  figure,  the  vapors  being 
omitted.  Its  top  was  high  above  the  rim  of  the  Halema'u- 
ma'u basin,  owing  to  the  rise  which  had  taken  place.     The 


'-■      -I    .^-..-.AffllfflMyEfeJH^dV  ^:>...'-j^!^  .1  J-i-^:   >gZ5am ^^^  ^''-:~g^ 


Cone  in  Halema'uma'u,  August,  1887. 

cone  was  found  to  be  literally  a  debris-cone,  not  a  lava-cone 
or  cinder-cone  in  any  part ;  and  the  debris  was  like  that  of 
fallen  walls  of  lava,  not  of  loose  scoria  such  as  might  have 
come  from  the  central  vent  of  a  cone.  No  eruptions  of  lava 
or  scoria  from  the  central  depression  had  been  at  any  time 
observed,  and  there  was  no  evidence  visible  over  the  surface 
that  any  such  ejections  had  taken  place.  In  the  night  view 
from  the  Volcano  House  the  dense  vapors  on  the  east  and 
west  sides  were  lighted  from  the  lavas  below,  but  none  over 
the  centre  of  the  cone,  where  there  was  apparently  only 
feeble  action. 

In  the  basin  about  the  cone,  the  chief  boiling  lava-lake 
was  on  the  west  side,  in  full  view  from  the  top  of  the  west 
wall.  The  lake  was  about  lijO  by  175  feet  in  its  diameters. 
Although  mostly  crusted  over,  it  showed  the  red  fires  in  a  few 
long  crossing  lines  (fissures),  and  in  three  to  five  open  places, 
half-way  under  the  overhanging  rock  of  the  margin  where 
the  lavas  were  dashing  up  in  spray  and  splashing  noisily, 
with  seemingly  the  liquidity  of  water.  Now  and  then  the 
fire-places  widened  out  toward  the  interior  of  the  lake, 
breaking  up  the  crust  and  consuming  it  by  fusion  ;  yet  at 
no  time  was  there  a  projection  of  the  lavas  in  vertical  jets 
in  a  free-boiling  way  ;  nor  was  it  too  hot  to  stand  on  the 
border  of  the  lake  if  only  the  face  were  protected.  Al- 
ia 


114  VOLCANIC   PHENOMENA 

though  relatively  so  quiet,  the  mobility  of  the  brilliant 
splashing  lavas  made  it  an  intensely  interesting  sight. 
Occasionally  the  red  fissures  widened  by  a  fusing  of  the 
sides  as  the  crust  near  by  heaved,  and  the  lavas  flowed 
over  the  surface.  It  was  evident  from  the  cooled  streams 
outside,  that  now  and  then  more  forcible  movements  take 
place,  followed  by  outflows  over  the  margin ;  when  the 
whole  lake  is  in  action.  There  were  no  true  well-defined 
jets  rising  and  falling  over  any  part  of  the  surface,  like 
those  of  1840,  —  a  condition  requiring  a  little  more  heat; 
but  the  splashing  at  the  margin,  also  due  to  the  escape  of 
vapor-bubbles,  had  all  the  freedom  of  movement  of  splashing 
waves  on  a  sea-coast.  The  existence  of  the  half-covered 
caverns  along  the  margin,  which  the  descriptions  show  to 
have  been  the  most  common  feature  for  a  score  of  years, 
was  owing  to  the  protection  from  cooling  given  by  the 
overlying  rock.  All  parts  of  the  basin  had  been  overflowed 
from  fissures  or  temporary  lava-pools. 

One  of  the  striking  features  of  the  cooled  lava-streams 
over  the  bottom  of  Kilauea,  and  also  of  those  outside,  over 
its  slopes  and  over  those  of  Mount  Loa,  are  the  series  of  par- 
allel curved  wrinkles,  which  give  the  look  of  tapestry  folds 
to  the  surface.  They  are  well  shown  in  the  following 
photograph  (Plate  VII.),  which  gives  a  good  general  idea  of 
the  floor  of  Kilauea  as  left  by  the  lava-flooding  of  1885. 

While  looking:  at  the  small  western  lava-lake  in  Halema'u- 
ma'u,  which  has  since  been  named  the  "  Dana  Lake,"  the 
making  of  the  tapestry-like  folds  was  well  exemplified.  A 
stream  of  lava  came  out  from  beneath  the  wall  of  the  debris- 
cone  and  flowed  obliquely  across  the  lake,  making  the  folds 
or  wrinkles  by  its  onward  movement  in  the  thin  crust  which 
surface-cooling  had  produced  ;  and  the  wrinkles  were  convex 
down-stream  because  of  the  greater  velocity  at  centre.  The 
accompanying  figure  represents,  reduced,  a  small  portion  of 
the  stream.     The  wrinkles  also  formed  over  the  lake  along- 


.Vt, 


IN   THE   HISTORY   OF   KILAUEA. 


117 


side  of  fissures  in  the  softened  and  nearly  melted  crust.  At 
one  time  a  lateral  shove  took  place  along  one  of  the  fissures 
in  the  crust  of  the 
lake,  and  the  next 
moment  the  margin 
was  rolled  over  into 
a  long  fold  or  wrin- 
kle, and  then,  by  the  more  rapid  movement  of  the  middle 
portion,  a  large  part  of  the  fold  became  twisted  into  a  rope. 
Thus  fold  follows  fold,  and  a  group  or  series  of  rope-like 
folds  results. 

The  tapestry-like  folds  of  the  surface  of  streams  are  some- 
times folds  simply  in  the  scoria-crust ;  but  they  commonly 
consist  of  the  more  solid  lava  also,  or  of  that  alone  in  case 
the  scoria-crust  is  absent.  Sometimes,  in  connection  with  the 
making  of  the  long  ropes,  the  crust,  where  thin,  becomes  bent 
upward  so  as  to  have  a  long  empty  space  a  foot  or  two  deep 
beneath  the  brittle  cover.  It  is  a  trap  for  the  incautious 
traveller,  but  it  usually  startles  without  injuring,  yet  serves 
to  j)oint  a  paragraph  about  the  dangers  of  the  crater. 

Over  the  bottom  of  the  crater  there  were  many  bulgings 
of  the  lavas  into  oven-like  shapes,  having  a  height  of  fifteen 
to  twenty  feet.  Such  bulgings  are  common  over  all  lava- 
streams,  and,  as  already  stated,  are  often  called  "  billows  '* 
and  hummocks,  and  some  of  them  have  twice  the  height  of 
any  seen  in  Kilauea.  They  look  as  if  they  had  been  pro- 
duced by  a  sudden  generation  of  vapors  from  some  volcanic 
source  beneath  or  from  water  or  moisture  passed  over  by  the 
flowing  stream. 

In  many  places  evidence  was  plain  that  the  bulging  had 
taken  place  after  the  flow  of  a  lava-stream,  though  before 
complete  consolidation.  This  evidence  was  afforded  by  the 
tapestr}^  folds  on  the  bulged  surfaces,  they  being  upside  down  ; 
that  is,  the  folds  were  often  convex  upward  instead  of  down- 
ward, as  in  the  following  figure.     The  tapestry  folds  indicate 


118  VOLCANIC  PHENOMENA 

the  direction  of  movement ;  and  when  thus  npside  down, 
they  prove  that  they  had  been  turned  out  of  their  original 
position.  These  bulgings  or  domes  are  generally  more  or 
less  cavernous  within,  and  sometimes  cover  large  chambers ; 
they  have  usually  broken  sides  with  some  displaced  blocks, 
as  here  represented.     The  breaking  up  of  such  domes  seemed 


to  be  due  in  part  to  contraction  and  want  of  support  through 
the  cavernous  condition  beneath.  Some  of  those  in  the  crater 
had  evidently  been  further  crushed  by  the  push  of  a  subse- 
quent lava-flow. 

The  sulphur  vapors  probably  take  part  in  the  making  of 
such  dome-shaped  elevations.  And  when  so,  the  space  below 
may  have  the  roof  covered  with  a  crust  and  stalactites  of 
glauber  salts,  or  with  a  thin  crust  of  gypsum,  as  often  met 
with  in  Kilauea,  the  vapors  having  contributed  material  for 
the  sulphuric  acid,  and  the  labradorite  of  the  lavas,  the  soda 
or  lime. 

Throughout  the  crater  the  lavas  had  the  thin,  fragile,  or 
separable  scoria-crust  or  scum,  mentioned  on  page  70  as 
characteristic  of  lavas  from  the  overflow  of  boiling  lakes  of 
1840.  But  this  crust  appeared  to  be  thinner  than  it  was  in 
1840,  —  only  one  to  two  inches  thick  instead  of  two  to  four, 
as  then  reported.  And  as  there  was  vastly  greater  freedom 
in  the  ebullition  in  1840,  it  may  well  be  that  the  scum  of  the 
boiling  vats  of  that  period  was  much  thicker  than  now. 

But  some  of  the  lava  streams  have  no  crust.  This  results 
when  the  lava  of  an  outflow  exudes  through  fissures  made  in 
the  hardened  crust  that  covers  it,  or  when  it  comes  up  through 
deep   fissures,   and   is  not    derived    from   the    boiling  lakes. 


IN   THE   HISTORY   OF   KILAUEA.  119 

Such  lava  is  ordinarily  glassy  for  half  an  inch  or  less  ex- 
ternally, but  instead  of  being  scoriaceous,  the  glass  is  nearly 
solid  and  part  of  the  solid  lava.  The  lava  flowing  beneath 
the  crust  of  cooled  rock  had  parted  with  its  scum,  and  that 
from  great  depths  never  had  any. 

The  occurrence  of  msilile  flames  at  night  over  the  liquid 
or  semi-liquid  lavas  of  Halema'uma'u,  observed  by  Mr.  Brig- 
ham  and  mentioned  on  pages  88,  96,  was  one  of  the  inter- 
esting points  confirmed  at  the  time  of  the  author's  visit  of 
1887.  They  were  seen  to  rise  within  the  area  of  the  lake 
where  heavings  and  breakings  of  the  lava-crust  took  place, 
and  not  where  the  fires  were  most  active.  The  flames  were 
one  to  three  feet  in  height.  They  were  very  pale  in  color, 
and  slightly  greenish  rather  than  bluish.  The  author  does 
not  claim  himself  to  have  seen  the  flames,  —  the  rains  of  the 
evening  and  a  cold  from  a  thorough  wetting  on  a  long  excur- 
sion having  prevented  his  joining  the  party.  But  critical 
observers  were  of  the  number,  —  as  Mr.  Emerson  of  the  Gov- 
ernment Survey,  President  Merritt  of  Oahu  College,  Rev.  S.  E. 
Bishop,  and  others,  —  and  the  testimony  was  unanimous. 

In  September,  1887,  a  month  or  so  after  the  author  left 
the  volcano,  the  photograph  of  the  Halema'uma'u  cone  was 
taken  which  is  reproduced  on  Plate  VIII.  It  is  essentially 
the  same  as  the  cone  of  August.  The  change  since  the 
spring  of  1887  is  apparent  in  the  longitudinal  division  of  the 
west  wall  into  two,  so  that  the  vapors  rise  east  of  a  western 
section  for  nearly  the  whole  length.  The  great  cone  was 
evidently  in  process  of  dissolution. 

By  March  8,  1888,  the  cone  had  risen  so  high  that  the 
summit  was  "  on  a  line  with  the  outside  walls  of  the  crater 
beyond  it,  looking  from  the  Volcano  House  ; "  and  the  floor 
of  the  basin  had  risen  likewise,  so  as  to  be  but  forty  or  fifty 
feet  below  the  top,  —  facts  which  imply  a  rise  of  thirty  or 
forty  feet  since  the  middle  of  August,  1887.     Moreover,  the 


120 


VOLCANIC   PHENOMENA 


eastern  side  of  the  cone,  which  appeared  to  be  partly  separate 
in  the  later  photograph  (Plate  VIII.),  -'has  slipped  down 
a  little  and  changed  considerably  in  shape."  ^ 

In  July,  1888,  Mr.  F. 
S.  Dodge  made  a  new 
survey  of  Halema'uma'u.^ 
He  found  the  basin  near- 
ly obliterated  by  the  rise 
of  its  floor,  and  only  fif- 
teen to  twenty  feet  above 
it  where  highest. 

The  accompanying 
map  and  sections  2  to  5 
present  the  chief  results 


(l 

\,-jJlJ 

J 

"^ 

\ 

^^ 

L__ 

E 

. 

F 

1.  Map  of  Halema'uma'u  in  July,  1888,  by  Mr.  F.  S.  Dodge,  reduced  to  one  fourth. 
2  to  5.  A  B,  C  D,  E  F,  G  H,  courses  of  the  sections.  2  to  5.  Sections  by  Mr.  Dodge 
of  Halema'uma'u  in  July,  1888. 

of  his  survey.  The  scale  of  the  map  is  two  thousand  feet 
to  the  inch,  which  makes  the  distance  across  the  basin 
from  east  to  west  (New  Lake  not  included)  a  little  over 
three   thousand    feet.       The    outline    of    the    debris-cone    at 

^  Mr.  J.  H.  Maby,  of  the  Volcano  House,  American  Journal  of  Science,  1888, 
xxxvi.  14. 

2  American  Journal  of  Science,  1889,  xxxvii.  48.  See  also  a  letter  from  Presi- 
dent Merritt,  Ibiel.,  p.  52. 


P-    G 


IN   THE   HISTORY   OF   KILAUEA.  123 

base  is  approximately  indicated  by  the  dotted  line.  The 
numbers  give  the  level,  below  the  Volcano  House  datum, 
of  three  points  at  the  top  of  the  cone  as  well  as  of  the 
floor  of  the  basin  and  of  the  crater  outside.  At  m,  n,  o,  p, 
q,  r  are  small  discharging  cones,  ten  to  twenty  feet  high. 
Two  of  these  small  cones,  m  and  n,  were  at  such  a  height, 
owing  to  the  rising  of  the  floor  of  the  basin,  that  their 
lava-streams  overflowed  the  rim  of  the  basin  ;  and  from  o  the 
lavas  had  flowed  into  New  Lake,  s  and  t  are  the  higher 
summits  of  the  cone,  and  ''  New  L."  means  New  Lake. 

Figs.  2  to  5  are  four  profile  sections  by  Mr.  Dodge  (A  B, 
C  D,  E  F,  G  H)  of  the  basin  and  its  cone.  The  height  in  these 
sections  is  exaggerated  five  times  ;  the  scale  is  made  four 
hundred  feet  to  the  inch,  and  the  horizontal  two  thousand 
feet ;  but  in  Fig.  2,  the  profile  a  b  has  the  true  proportions. 
In  2  and  3,  p  is  the  pit  within  the  debris-cone.  No  attempt 
to  obtain  the  depth  could  be  made  on  account  of  the  discharg- 
ing vapors,  e  is  the  edge  of  the  basin  of  Halema'uma'u ;  I, 
Dana  Lake.  The  projection  above  the  floor  of  New  Lake  in 
Fig.  .3  is  due  to  the  ''  stranded  floating  island." 

The  time  from  March,  188G,  to  July,  1888,  a  little  over 
two  years,  was  sufficient  for  the  refilling  of  the  deep  basin  of 
Halema'uma'u  and  also  of  New  Lake,  and  for  the  renewal 
of  the  great  outflows  over  the  floor  of  the  crater.  This 
condition  continued  until  May,  1889,  when,  as  I  learn  from 
Mr.  Baker,  there  was  a  subsidence  of  eighty  feet  in  the  floor 
of  Halema'uma'u,  which  carried  down  the  large  central 
debris-cone,  and  all  else  on  the  floor,  and  made  walls  of 
eighty  feet  again  about  the  great  depression.  Dana  Lake 
was  between  the  walls  and  the  cone  ;  but  on  July  4  it  was 
as  active  as  usual,  and  a  stream  flowed  froui  it  toward  the 
cone.  A  stream  of  lava  issued  in  May  from  a  fissure  in  the 
floor  of  Kilauea,  some  distance  from  Halema'uma'u ;  and  this 
appears  to  have  drawn  off  the  lavas  beneath  the  floor  of  the 
basin,  and  so  dropped  it  down  the  eighty  feet. 


124  volcanic  action. 

5.  General   Summary,   with   Conclusions. 

From  the  foregoing  review  of  publications  on  Kilauea,  it 
appears  that  the  knowledge  we  have  about  the  changes  in 
the  crater  embraces  facts  that  are  fundamental  to  the  science 
of  volcanic  action.  This  will  be  made  more  apparent  by  the 
Summary  and  Conclusions  which  follow.  It  will  be  conven- 
ient to  consider,  first,  the  Historical  Conclusions,  and,  sec- 
ondly, the  Dynamical. 

I.   HISTORICAL   CONCLUSIONS. 

1.  Periodicity  or  not  in  the   Discharges  op  Kilauea. 

In  the  sixty-three  years  from  1823  to  1886,  there  appear 
to  have  been  at  least  eight  discharges  of  Kilauea.  Four  of 
them  were  of  prime  magnitude,  —  those  of  1823,  1832,  1840, 
and  1868,  —  distinguished  by  a  down-plunge  in  the  floor  of 
the  crater,  making  in  each  case  a  lower  pit  several  hundred 
feet  deep.  Others,  as  those  of  1849,  1855,  1879,  1886,  were 
minor  discharges,  discharges  simply  of  the  active  lakes,  with- 
out any  appreciable  or  noticed  sinking  of  the  floor  of  the 
crater.  The  eruption  of  1849  may  be  questioned.  Other 
subterranean  discharges  may  have  occurred  since  1840,  of 
which  no  record  exists.  Even  small  breaks  below  might 
empty  Halema'uma'u ;  and  they  often  do  more  or  less,  as 
the  floor  of  Kilauea  l)etween  eruptions    rises. 

The  mean  length  of  interval  between  the  first  three  erup- 
tions was  eight  to  nine  years.  The  great  eruption  of  1789,  the 
only  one  on  record  before  that  of  1823,  occurred  thirty-four 
years  back  of  1823,  or  4X8^  years  ;  and  the  1868  eruption 
was  3X9^  years  after  that  of  1840. 

The  above  approximate  coincidences  in  interval  and  multiples 
of  that  interval  seem  to  favor  some  law  of  progress.  But  it 
is  not  yet  proved  that  they  have  any  significance.  The  minor 
eruptions  which  have  been  referred  to  above  have  intervals 


PROGRESSIVE   CHANGES   IN  KILAUEA.  125 

varying  from  six  to  thirteen  years.  Moreover,  looking  to  the 
summit  crater  of  Mount  Loa  for  its  testimony,  we  find  still 
greater  irregularity,  the  successive  intervals  between  its  six 
great  outflows  from  IS'iS  to  1887  being  S^,  4,  3i  9,  12i  and 
6|-  years. 

Dependence  of  the  Actwitij  on  Seasons  of  Rains.  —  A  re- 
lation to  the  rains  was  suggested  by  Mr.  Coan  ;  and  there  is 
some  foundation  for  the  opinion  in  the  fact  that  the  times  of 
occurrence  of  the  Kilauea  discharges  come  mostly  within  the 
four  months,  March  to  June,  as  shown  in  the  following  table : 

1823     Marcli?  1849     May.  1879     April  21. 

1832     June  (Jan.?)  1855     October.  1886     Mardi  6. 

1840     May.  1868     April  2. 

In  addition,  there  was  a  brightening  of  the  fires  around 
the  crater  in  October  of  1863,  and  again  in  May  and  June 
of  1866 ;  whether  followed  by  a  discharge  of  the  Great 
Lake  or  not  is  not  known.  The  future  study  of  the  crater 
should  have  special  reference  to  this  supposed  meteorological 
connection. 

2.  Mean   Rate   of   Elevation   op   the   Floor   of   the   Crater 
AFTER   the   Great   Eruptions. 

After  the  eruption  of  1823,  between  the  spring  of  that 
year  and  October  of  1829,  an  interval  of  6|-  years,  the 
bottom,  if  the  depth  was  800  feet  as  inferred  after  the 
measurement  of  the  upper  wall  by  Lieutenant  Maiden,  rose 
at  a  mean  annual  rate  of  138  feet,  or,  taking  the  depth  at 
600  feet,  of  93.3  feet.  Lieutenant  Maiden's  900  feet  for 
the  upper  wall,  sustained  after  explanation  on  page  51, 
may  need  reduction,  on  the  ground  that  the  present  width 
of  the  crater  is  greater  than  in  1825,  owing  to  falls  of  the 
walls  ;  but  it  is  useless  with  present  knowledge  to  make 
any  definite  correction.     Only  general  results  are  possible. 

After  the  1832  eruption  the  lower  pit  in  February  of 
1834  was    362  feet    deep,  by  the  barometric    measurement 


126  VOLCANIC  ACTION. 

of  Mr.  Douglas,  as  explained  on  page  57  ;  and  in  May  of 
1838,  about  4i  years  later,  it  was  filled  to  within  forty 
feet  of  the  top ;  whence  the  mean  annual  rate  of  71|^ 
feet. 

After  the  1840  eruption,  between  January,  1841,  and  the 
summer  of  1846,  5|-  years,  the  342  feet  of  depth,  found  for 
the  lower  pit  by  the  Wilkes  Expedition,  was  obliterated,  and 
the  floor  was  raised  on  an  average  forty  or  fifty  feet  beyond 
this ;  a  rise  of  400  feet  in  the  6^  years  would  give,  for  the 
mean  annual  rate,  72|  feet. 

Subsequent  to  1846  the  rising  of  the  floor  was  slower. 
Between  1846  and  1868,  twenty-two  years,  the  rise  over 
the  central  plateau  is  estimated  at  two  hundred  feet.  It  is 
not  certain  that  subsidences  in  the  plateau  of  greater  or 
less  amount  did  not  take  place  at  the  eruptions  of  1849  and 
1855,  or  at  other  times. 

3.  Levels  op  the  Floor   after  the  Eruptions  op  1823, 
1832,   1840,   1868,   and   1886. 

The  measurements  of  depth  already  given  and  the  mean 
annual  rate  of  progress  deduced  are  approximate  data  for 
determining  the  depth  of  the  lower  pit  as  it  existed  imme- 
diately after  the  great  eruptions. 

The  depth  after  the  1823  eruption  is  considered  above. 
To  arrive  at  the  depth  after  the  1832  eruption,  the  depth 
obtained  in  1834  by  Douglas  has  to  be  increased  by  an 
allowance  for  change  during  the  previous  year  and  a  half, 
which,  at  the  rate  arrived  at  above,  would  give  four  hun- 
dred and  fifty  feet.  This  is  so  much  less  than  the  estimate 
of  Mr.  Goodrich,  mentioned  on  page  56,  that  it  is  almost 
certainly  below  rather  than  above   the  actual  fact. 

For  the  depth  in  June,  1840,  the  Wilkes  Expedition 
measurement  (342  feet)  should  be  increased  for  a  preceding 
interval  of  seven  months,  which,  at  the  rate  deduced  above 
for  the  next  four  years,  would  make  the  amount  about  385 


PROGRESSIVE    CHANGES   IN   KILAUEA.  127 

feet.  In  1868,  according  to  the  two  estimates  for  the  lower 
pit,  the  depth  was  about  three  hundred  feet.  Mr.  Severance, 
of  Hilo,  informed  me,  in  August,  1887,  that  the  pit  in  1868  was 
as  deep  as  in  1840.  The  lower  estimate  is  adopted  beyond. 
In  1880,  the  lower  pit  of  1868  had  wholly  disappeared,  and, 
according  to  the  description  of  Mr.  Brigham  (p.  1)6),  the  bot- 
tom of  the  crater  had  already  the  form  of  a  low  eccentric  cone, 
the  surface  rising  from  the  foot  of  the  encircling  walls  to  the 
summit  about  Halema'uma'u.  Tliis  has  continued  to  be 
the  form  of  the  bottom,  and  the  Government  map  gives 
the  present  depth.      (See  Plate  III.) 

The  following  table  contains  the  above  deduced  figures  for 
the  depth  of  the  lower  pit,  the  height  of  the  highest  imrt  of 
the  western  wall,  and  the  level  of  the  centre  of  the  pit 
below  the  top  of  the  western  wall. 


Depth  of  Lower  Pit. 

Height  of  Western  Wall 
above  Ledge. 

Hei 

ght  of  Western  Wall 
above  Centre  of 
Bottom. 

After  eruption  of  1823 

600     (800?) 

900  (?)  Maiden 

1,500     (1,700?) 

18.32 

450     (600?) 

715  Douglas 

1,165     (1,315?) 

1840 

385 

650  Wilkes  i 

1,030 

1868 

300 

600     (550?) 

900      (850?) 

1886 

0 

500  Gov't  Survey 

380 

These  numbers  have  much  instruction  in  them,  notwith- 
standing all  uncertainties.     The  following  diagram  based  on 


.too 

.1000 

18S8 
1S46 

i 

tz: 

1^^^ — 

y 

^00 

1832 

them  represents  a  transverse  section  of  the  crater  at  the  sev- 
eral levels  of  the  floor  and  black  ledge.  The  minimum 
depths  for  1823  and  1832  are  here  accepted,  there  being  in 
them  no  probability  of  exaggeration. 

The   sides   of  the   pit   in    this    section   are  made   vertical 

^  The  Wilkes  Expedition  appears  to  have  made  the  place  of  encaiiipnicTit  tlie 
datum  point.  It  was  just  west  of  the  solfatara  depression,  but  the  exact  position  is 
not  precisely  known. 


128  VOLCANIC   ACTION. 

from  1823  onward,  —  an  error  which  there  are  no  data 
for  correctmg. 

The  dimmution  since  1823  in  the  height  of  the  western 
wall  above  the  black  ledge  is  probably  due  almost  wholly  to 
the  floodhuj  of  the  black  ledge.  iVccording  to  the  numbers 
this  diminution  was  about  a  hundred  and  eighty-five  feet 
from  1823  to  1832,  sixty-five  from  1832  to  1840,  and  one 
hundred  and  sixty  feet  since  1810.  But  subsequent  to  1840, 
as  Emerson's  map  shows,  the  diminution  of  level  along  the 
black  ledge  or  lateral  portion  of  the  pit  has  been  much  less 
than  over  the  central,  the  amount  of  diminution  at  centre 
havino;  been  at  least  two  hundred  feet,  and  about  Hale- 
ma'uma'u  two  hundred  and  fifty  to  three  hundred  feet. 

The  bottom  of  the  emptied  basin  of  Halema'uma'u  after 
the  eruption  of  1886  was  nine  hundred  feet  below  the  Vol- 
cano House ;  and  this  was  fifty  to  a  hundred  feet  above  the 
liquid  lava  of  the  basin  in  1840. 

Tlie  relations  hetween  the  amounts  discharged  in  1823,  1832, 
1840,  and  1868  could  be  approximately  inferred  from  the 
size  of  the  lower  pit  as  determined  by  the  mean  breadth  of 
the  black  ledge,  if  the  width  of  the  crater  were  the  same  at 
all  periods.  But  in  addition  to  other  uncertainties  we  have 
that  arising  from  sloping  walls,  —  and  very  sloping  on  the 
southeast  side.  The  pit  of  1823  should  therefore  have  been 
narrower  at  the  black-ledge  level  than  that  of  1840.  Still 
the  width  of  the  ledge  in  1823,  according  to  all  the  observa- 
tions and  maps,  was  so  very  narrow  compared  with  that  in 
1840  that  we  may  feel  sure  of  the  far  larger  amount  of  the 
earlier  discharge.  But  the  depth  of  the  lower  pit  was  also 
greater  in  1823  ;  and  this  requires  an  addition  of  one  half  to 
the  amount  which  the  area  of  the  lower  pit  suggests,  if  not  a 
doubling  of  it. 

For  an  estimation  of  the  discharge  of  1832  we  are  still 
more  uncertain  as  to  the  mean  width  of  the  ledge.  But  that 
the  ledo-e  was  narrow  —  much  like  that  of   1823  —  is  most 


PKOGEESSIVE   CHANGES   IN   KILAUEA.  129 

probable.  In  1868  the  down-plimge.  according  to  the  most 
reliable  estimate,  was  a  fourth  less  than  in  1840,  the  depth 
of  the  pit  being  not  over  three  hundred  feet. 

There  are  no  sufficient  data  for  putting  in  figures  the  rela- 
tive amounts  of  discharge  at  the  great  eruptions.  But  the 
general  fact  of  a  large  diminution  in  the  amounts  since  the 
first  in  182o  is  beyond  question.  It  has  to  be  admitted, 
however,  that  we  can  hardly  estimate  safely  the  discharge  in 
1868  from  the  size  of  the  pit  then  made,  since  the  thickness 
of  the  solid  floor  of  the  crater  may  have  prevented  as  large  a 
collapse  in  proportion  to  the  discharge.  But  it  did  not  take 
place  until  twenty-eight  years  had  passed  after  1840,  and 
this  strengthens  the  evidence  as  to  an  apparent  decline  in 
the  outflows,  whatever  be  true  as  to  the  activity.  The  fol- 
lowing eighteen  years  produced  only  minor  eruptions. 

4.  Progress  in  Halema'uma'u  since  the  Eruption  of  March,  1886. 

In  April,  1886,  a  month  after  the. eruption,  Mr.  J.  S.  Em- 
erson found  the  basin  590  feet  in  depth  at  middle,  and  175  to 
200  feet  decD  over  a  broad  border  reg;ion.  The  condition  is 
represented  approximately  (from 
Mr.  EmxCrson's  measurements)  in 
the  profile  section  A.  The  cone 
had  already  become,  by  Professor 
Van  Slyke's  estimate,  a  hundred 
and  fifty  feet  high  in  the  next 
three  months.  The  sections  across 
the  basin  through  the  cone  B,  C, 
D,  illustrate  the  progress  in  the 
lifting  of  the  cone  and  the  floor  of 
the  basin,  B  l^eing  the  condition  re- 
ported in  Mr.  Dodge's  survey  of  the  first  week  of  October,  — 
six  months  after  Mr.  Emerson's  survey,  when  the  highest 
peak  of  the  cone  was  only  two  to  five  feet  above  the  rim  of 

17 


130  VOLCANIC   ACTION. 

the  basin  ;  C,  that  approximately  at  the  time  of  the  author's 
visit  in  August,  1887  ;  and  D  that  of  Mr.  Dodge's  last  survey 
in  July,  1888,  when  the  cone  was  almost  wholly  emerged. 

From  the  levels  obtained  by  Mr.  Dodge  at  his  two  sur- 
veys in  October,  1886,  and  July,  1888,  and  by  Mr.  Emerson 
in  April,  1888,  we  have  data  for  determining  the  rate  of 
change  of  level.  (1)  The  change  in  the  western  rim  of 
Halema'uma'u  was  nothing;  (2)  in  the  summit  s,  167.2  feet; 
in  the  summit  t,  171.4  feet.  The  time  during  which  this 
rise  of  approximately  170  feet  took  place  was  about  650  days, 
giving  for  the  mean  daily  rate  of  rise  3.15  inches.  The  rise 
was  most  rapid  during  the  first  year,  Mr.  Dodge  making  the 
rate  in  October,  1886,  a  foot  a  day. 

The  small  ejections  going  on  over  the  basin  outside  of  the 
cone  during  the  two  years  past,  raised  to  some  extent  the 
level  of  the  floor.  But  whatever  the  amount  it  does  not 
affect  the  calculation,  this  being  based  on  changes  in  the 
level  of  the  summit,  which  received  no  additions  from  ejec- 
tions or  any  other  source. 

The  conclusion  of  Mr.  Dodge  that  the  cone  within  Hale- 
ma'uma'u and  the  floor  of  the  basin  about  it  had  been 
"  floated  upward  "  on  the  rising  lavas  a|3pears,  therefore,  to 
be  the  only  satisfactory  explanation  of  the  change  of  level. 

Finally,  in  May  of  1889,  an  eruption  over  the  floor  of 
Kilauea  (or  some  other  way  of  discharge)  dropped  the  floor 
of  Halema'uma'u,  with  the  cone,  eighty  feet  again,  restoring 
nearly  the  condition  of  August,  1887.  This  is  the  ordinary 
way  with  Halema'uma'u.  Its  discharges  from  time  to  time 
help  in  the  raising  of  the  Kilauea  floor,  and  in  the  process 
its  own  floor  loses  in  level. 

5.  Other  Points  in  the  Topographic  History  op  the  Kilauea 

Region. 

Besides  the  points  considered,  the  chief  events  in  the  topo- 
graphic history  since  1823  are  (1)  avalanches  and  subsidences 


PEOGRESSIVE   CHANGES   IN    KILAUEA.  131 

along   tlie    Ixjrder  of    tlie  crater,  and    (2)   overflowings  and 
chano-es  of  level  over  the  bottom. 

o 

Down-falls  of  the  walls  and  sinkings  of  the  l)orders  are 
reported  as  having  been  common  during  periods  of  eruption 
and  earthquake  ;  but  direct  testimony  as  to  the  amount  at 
any  time  does  not  exist. 

Besides  the  great  fissures  of  the  northern  border  of  the 
crater,  near  the  path  of  descent,  with  the  subsided  belts  be- 
tween, and  the  many  fissures  of  the  solfatara  depression  just 
back,  others  exist  farther  north  and  east,  to  a  limiting  wall, 
about  forty  feet  high,  which  is  evidently  a  fault-wall.  This 
wall  is  about  two  thousand  feet  from  Kilauea  at  the  northwest 
corner,  and  diverges  eastward  to  about  five  thousand  feet, 
and  then  bends  around  southward  so  as  to  embrace  Kilauea- 
iki  within  the  large  northern  border  region  of  fissures  and 
subsidence. 

Deep  and  wide  rents  extend  also  along  the  whole  western 
border  of  Kilauea,  generally  two  or  more  together ;  and.  near 
the  highest  station,  Uwekahuna,  there  were  six  of  them, 
parallel  to  one  another,  in  August,  1887.  South  of  this 
station,  between  it  and  the  southwest  angle  of  the  crater, 
the  fissures  are  continued  over  a  large  depressed  border, 
five  to  fifteen  hundred  feet  wide,  lying  between  a  precip- 
itous ridge  —  fault-plane  —  on  the  west  and  the  crater. 
North  of  Uwekahuna  the  evidences  of  subsidence  visil)le  in 
1887  were  small  j  but  south  of  it  the  surface  had  different 
terrace-levels,  showing  great  and  various  sinkings  of  the  sur- 
face. Almost  in  front  of  Uwekahuna,  bordering  the  Kilauea 
wall,  there  was  a  surface,  200  to  208  feet  below  the  level  of 
this  station,  according  to  the  Government  maps,  which  is 
plainly,  as  seen  from  below,  a  result  of  subsidence  ;  and  vari- 
ous other  terrace-levels  existed  farther  south.  On  the  east 
side  of  Kilauea  also  there  are  fissures  parallel  to  the  walls ; 
and  large  depressed  areas  exist  between  Kilauea  and  the  two 
adjoining  craters.     Fissures  extend  northward  to  the  east  of 


132  VOLCANIC   ACTION. 

Kilaiiea-iki,  as  noticed  by  the  Wilkes  Expedition  in  1840, 
and  new  openings  there,  near  the  Keauhon  road,  were 
reported  as  opened  in  March,  1886,  at  the  time  of  the 
eruption. 

The  wall  on  the  northeast  side  of  Kilauea  near  the  path  of 
descent,  called  Waldron's  Ledge  (after  a  purser  in  the  Wilkes 
Expedition),  is  one  of  the  highest  and  most  stable  parts  of  the 
walls,  being  but  eleven  and  a  half  feet  below  the  level  of  the 
Volcano  House  datum.  It  is  a  bare-faced,  vertical  precipice, 
showing  stratified  lavas  to  the  top.  Like  Uwekahuna,  it 
seems  to  be  an  exception  to  border  instability.  But  it  stands 
on  the  brink  of  the  most  unstable  region,  —  that  of  the  north 
side.  In  a.  walk  along  the  base  of  the  precipice  there  was  in 
August,  1887,  a  freshly  uncovered  portion  of  the  rock  at 
bottom  for  a  height  of  two  to  three  inches,  showing  that  a 
recent  sinking  adjoining  it  had  taken  place,  or  that  one  was 
then  in  progress. 

This  border-belt  of  fissures  and  subsidences,  if  reckoned  as 
part  of  the  Kilauea  iire-region,  or  region  of  disturbance,  adds 
five  thousand  feet  to  the  length  of  the  region,  and  nearly 
doubles  the  width  across  the  northern  half.  There  are  long 
fissures  also  over  the  region  southwest  of  the  crater,  some  of 
which  were  reported  by  the  Mission  Deputation  of  1823. 

It  is  an  interesting  and  important  fact  that  while  the 
fissures  about  the  northeast  end  of  Kilauea  are  concentric 
with  the  outline  of  the  crater  (Kilauea-iki  being  included 
with  it),  those  at  the  south  end  are  nearly  all  longitudinal, 
or  in  the  direction  of  the  longer  diameter,  southwestward. 
Moreover,  as  is  Avell  known,  tlie  latter  extend  on  for  twelve  to 
fifteen  miles  to  the  southwest.  There  are  many  of  them,  — 
more  than  is  shown  on  any  map  or  recorded  in  any  de- 
scription ;  and  some  are  very  deep  in  places,  giving  off  hot 
air.  steam,  and  sulphurous  acid  fumes  in  great  volume. 
While  some  of  them  date  from  1868,  and  others  from  1886, 
still  others  existed  back  of  all  records.     The  subsidence  that 


PKOGKESSIVE    CHANGES   IX    KILAUEA. 


138 


has  gone  on  over  this  southwestern  fissured  area  has  not  left 
any  satisfactory  evidence  of  its  amount.  We  know  only  that 
(as  the  Government  map  teaches)  the  surface  is  about  280 
feet  heloiv  the  level  of  the  Volcano  House,  and  395  feet  below 
that  of  the  Uwekahuna  station. 

In  view  of  the  great  numbers  of  deep  fissures  about 
Kilauea  and  the  many  fault-planes  and  sunken  areas,  the 
fact  of  extensive  subsidence  cannot  be  doubted.  Mr.  Bris:- 
ham  has  estimated  ^  that  the  crater  in  1880  was  five  per  cent 
larger  than  it  was  eighteen  years  before.  The  increase  in 
mean  diameter  on  this  estimate  would  be  three  hundred  feet. 
This  estimate  appears  to  be  much  too  large. 


KILAUEA 
U.  S.  EXPL.  EXPED. 


Of   the  gradual   changes  over   the   bottom   of  the   crater 
pretty  full  records  are  given  in  the  preceding  pages.    For  defi- 


^  American  Journal  of  Science,  1887,  3d  series,  xxxiv.  2(). 


134 


VOLCANIC   ACTION. 


nite  information  on  this  point,  and  especially  with  regard  to 
changes  in  general  outline,  we  should  naturally  look  with  the 
greatest  confidence  to  the  maps  that  give  the  results  of  personal 
surveys.  We  have  two  such  maps,  —  that  made  personally 
by  Wilkes  in  1841  and  that  by  Brigham  in  1865,  —  besides 
the  recent  map  by  the  Hawaiian  Government,  under  Professor 
Alexander's  charge,  completed  in   1880.     The   first  is  here 


KILAUEA 
WM.  T.  BRIGHAM 


referred  personally  to  Captain  Wilkes,  because  his  ''  Narra- 
tive "  says  :  "I  measured  my  base  and  visited  all  the  stations 
around  in  turn."  For  convenient  comparison  the  reduced 
copies  of  Wilkes's  and  Brigham's  maps  are  here  reproduced. 
For  that  of  the  Government  Survev,  see  Plate  III. 


PROGRESSIVE   CHANGES   IN    KILAUEA.  135 

In  using  the  maps  a  difficulty  is  encountered  at  the  outset 
in  consequence  of  a  discrepancy  between  the  first  two  of  the 
maps  and  that  of  the  Government  Survey  as  to  the  dimensions 
of  the  crater.  Accepting  the  latter  as  right,  the  scale  of  each 
of  the  others  should  be  diminished  about  an  eighth  to  bring 
the  three  maps  into  correspondence.  The  maximum  diam- 
eters in  Wilkes's  map,  using  his  own  scale,  are  16,000  and 
11,000  feet;  while,  according  to  the  Government  map,  they 
are  about  14,000  and  9,800  feet  ;  and  the  length  of  the  line 
from  K  to  B  on  the  former  is  10,000  feet,  and  on  the  latter 
8,500  feet.  It  is  certain  that  the  crater  in  1840  was  not 
larger  at  top  than  now.  Mr.  Brigham's  map  appears  to 
have  been  carefully  made,  but  for  some  reason  it  requires  the 
same  correction.  This  correction  makes  the  scale  of  Wilkes's 
map  5,000  feet  to  the  inch,  as  stated  on  page  65.  Such  a 
discrepancy  unavoidably  throws  doubts  over  other  parts  of 
the  maps.  But  while  closer  study  increases  confidence  in 
Mr.  Brigham's,  tlie  result  is  not  so  satisfactory  with  the 
Wilkes  map.  The  following  remarks  suppose  the  scale  of 
the  two  maps  to  have  been  corrected. 

Wilkes  s  Mcq)  of  Kilauea.  —  The  relations  of  the  map  made 
by  Captain  Wilkes  to  that  of  the  Government  Survey  is  ex- 
hibited on  Plate  IX.,  the  outline  of  the  crater  from  the  former 
being  drawn  over  the  latter  where  it  is  prominently  divergent. 
This  diverging  part  of  the  outline  is  lettered  ABODE; 
D  E  shows  the  outline  of  the  southeast  Sulphur  Bank  of 
1840.  Besides  this,  the  outline  of  the  black  ledge  of  1840 
is  indicated  by  the  line  L  L  L,  and  its  surface  by  cross-lining. 
Some  important  features  from  Brigham's  map  also  are  drawn 
in  and  indicated  by  italic  letters.  These  include  small  lava- 
lakes,  the  outline  of  Halema'uma'u  as  given  by  him,  small 
cones,  fissures,  etc. 

Plate  IX.  shows,  in  the  first  place,  a  general  conformity 
between  the  eastern  wall  of  the  Wilkes  and  the  Government 
maps,  but  a  far  greater  width  of  Sulphur  Banks  in  that  of 


136  VOLCANIC   ACTION. 

1840.  These  Sulphur  Banks  have  become  submerged  by  the 
lava-flows  of  later  time,  as  remarked  as  long  ago  as  1868  by 
Mr.  Brigham,  and  thus  the  floor  of  the  crater  has  in  this  part 
been  extended  eastward  about  twenty-five  hundred  feet. 
This  change  there  is  no  reason  to  doubt. 

In  the  second  place,  there  is  no  conformity  between  the 
maps  in  the  southern  half  of  the  western  wall.  On  the  con- 
trary, in  Wilkes's  map,  south  of  the  Uwekahuna  station,  the 
west  wall  (A  B  C,  on  Plate  IX.)  is  twelve  to  fifteen  hundred 
feet  inside  of  the  position  of  the  existing  wall  as  given  on 
the  Government  map ;  showing,  apparently,  a  very  great 
topographical  change  on  that  side  of  Kilauea  since  January, 

1841,  and  one  of  the  highest  interest,  —  a  change  that,  if  a 
fact,  had  been  brought  about  either  by  subsidence  or  by  over- 
flowings of  lava-streams,  and  had  added  nearly  ten  million 
square  feet  to  the  area  of  the  crater. 

Looking  about  for  other  evidence  of  this  change,  and  find- 
ing no  allusion  to  it  in  Mr.  Coan's  reports  on  the  crater 
during  the  period,  and  nothing  in  Mr.  Lyman's  paper  of 
1851  or  his  map  of  1846,  l3ut,  on  the  contrary,  a  general  con- 
formity in  Lyman's  map  to  that  of  the  recent  survey,  I  was 
led  to  question  the  unavoidable  conclusion,  although  it  in- 
volved a  doubt  of  the  Wilkes  map.  A  consequence  of  the 
doubt  was  my  sudden  determination  in  the  sunnner  of  1887 
to  revisit  Hawaii  and  sustain  the  conclusions  from  Wilkes's 
map  if  possible  ;  for  they  made  too  large  a  piece  in  the  his- 
tory to  be  left  in  doubt.  Mr.  Drayton's  sketch  (Plate  11.) 
suggested  the  method  of   deciding  the  question. 

The  conclusion  arrived  at  while  on  the  ground  was  that 
Drayton's  sketch  of  1840  represented  sufficiently  well  the 
jjresent  outline  of  that  part  of  the  crater  ;  that  is,  the  out- 
line of  the  crater  of  1887.  Consequently,  if  the  west  wall  in 
1840  had  essentially  the  same  position  as  in  1887,  Wilkes's 
map  of  the  southern  half  of  its  western  wall  is  twelve  to 
fifteen  hundred  feet  out  of  the  way. 


PROGRESSIVE   CHANGES   IN    KILAUEA.  137 

To  make  this  large  correction  on  Wilkes's  map  involves 
some  other  large  changes  ;  namely,  the  widening  of  the  black 
ledge  west  of  Halema'uma'u ;  and  also  a  widening  of  the 
Halema'uma'u  part  of  the  lower  pit  with  the  entrance-way 
to  it.  Both  changes  are  favored,  or  rather  required,  by 
Drayton's  sketch.  In  Plate  IX.  the  entrance- way  referred 
to  has  thus  been  widened  (on  the  ground  of  Drayton's  sketcli 
chiefly),  from  Wilkes's  eight  hundred  feet  at  top  of  wall  to 
about  fifteen  hundred  feet.  The  dotted  line  L'L'L'  on  the 
same  plate  is  beUeved  to  show  tlie  probable  limit  of  the 
1840  blaclv  ledg-e  alona;  the  west  border  of  Halema'uma'u.^ 

So  large  an  error  in  so  small  a  map  excites  an  uncomfort- 
able query  as  to  all  the  rest  of  its  details  ;  fortunately  not, 
however,  as  to  the  depth  of  the  cratei"  and  its  lower  pit,  since 
this  was  obtained  by  the  independent  measurements  of  two 
of  the  Expedition  officers.  Lieutenants  Budd  and  Eld.  More- 
over, the  map  may  be  used  for  some  general  conclusions. 

The  point  from  which  Drayton's  sketch  was  probably  taken 
is  marked  Dn  on  Plate  IX.  ;  this  is  south  of  Wilkes's  en- 
campment. It  ma}'  have  been  on  the  higher  land  just  west 
of  this  point.^ 

The  sketch  has  three  headlands  alons;  the  west  wall.  Of 
these,  only  the  second  and  third  exist  as  they  then  were. 
The  first  or  nearest  stood,  as  the  sketch  shows,  between  the 
Uwekahuna  summit  and  the  second  of  the  deep  western  bays 
on  Wilkes's  map  of  the  lower  pit,  —  a  spot  where  great  sub- 
sidence has  taken  place  in  the  western  wall,  east  or  south- 
east of  the  Uwekahuna  station  ;   and  the  sketch  appears  to 

^  Another  smaller  change  is  proposed  in  the  eastern  outline  of  the  lower  pit, 
near  e,  suggested  by  Brighani's  map.  No  attempt  is  made  to  give,  on  the  Govern- 
ment map,  Wilkes's  outline  of  the  southeast  angle  of  the  crater,  as  the  existing 
features  offer  no  available  suggestions. 

2  While  the  sketch  bears  evidence  of  being  generally  faitliful  to  the  facts,  the 
foreground  appears  to  be  modified  for  the  artistic  purpose  of  giving  distance  to 
the   rest. 

18 


138  VOLCANIC    ACTION. 

he  sufficient  testimony  for  the  reality  of  this  subsidence  and 
its  amount. 

Looking  again  at  Wilkes's  map,  on  page  loo,  it  is  seen  that, 
as  already  stated,  the  outer  eastern  wall  has  the  same  position 
that  it  has  on  the  Government  map,  ]:)ut  that  the  western 
wall  of  Wilkes  is  not  continuous  with  the  southeastern,  Imt  is 
an  independent  one  put  in  more  to  the  eastward  ;  and  here 
came  the  error.  The  error  is  so  extraordinarily  great  that 
we  sought,  while  at  the  crater,  for  some  extraordinary  excuse 
for  it.  We  concluded  (Mr.  Merritt  and  myself)  that  Captain 
Wilkes  in  his  visit  to  ''  all  the  stations  around  the  crater  in 
their  turn,"  on  reachiug  the  high  Uwekahuna  summit,  in- 
stead of  relying  on  his  angles,  probably  took  the  shorter  way 
of  sketching  in  the  ridges  that  stood  to  the  southeast  and 
south  ;  and  that  he  was  led  by  insufficient  topographical 
judgment  to  throw  the  wall,  together  with  the  parallel  ridge 
outside  of  it,  too  far  to  the  eastward.  The  error,  as  we  saW 
when  there,  is  an  easy  one  for  him  to  have  made.  This 
cramped  the  map  to  the  southward  aljout  the  Great  South 
Lake  ;  but  the  angles  taken  from  other  stations  were  not 
enough  to  serve  for  the  needed  correction,  and  the  sketching 
was  allowed  to  control  the  lines. 

An  important  error  also  exists  in  Wilkes's  determination 
of  the  longitude  of  his  encampment  near  the  crater.  The 
Surveyor-General  of  the  Islands,  Professor  Alexander,  in- 
formed me  that  the  position  Wilkes  gives  Kilauea  is  eight 
and  a  half  minutes  too  far  west ;  and  that  the  error  affects 
all  the  southeastern  quarter  of  his  map  of  Hawaii  including 
the  position  of  the  coast-line.  His  longitude  of  the  summit 
of  Mount  Loa  is  correct. 

Mr.  Brighams  Map.  —  Mr.  Brigham's  map  is  a  register 
of  the  facts  of  1864-1865,  a  period  just  half-way  be- 
tween 1841  and  1887.  It  indicates  unfinished  changes  in 
progress  within  the  crater  which  were  commenced  in  1840, 


PROGRESSIVE   CHANGES  IN   KILAUEA. 


139 


and  other  conditions  that   became  pronounced  only  in  Liter 
years. 

The  remnants  it  represents  of  Lyman's  ridge  of  lava-biocks 
—  the  talus  of  the  lower  wall  uplifted  upon  the  rising  lloor 


of  the  lower  pit,  and  the  same  on  Mr.  Perry's  sketch  —  have 
already  been  referred  to.  That  it  may  be  fully  appreciated, 
the  reader  is  directed  again  to  Mr.  Lyman's  map  al:)Ove,  and 
then  to  Plate  IX.,  which  shows  these  remaining  parts  of  the 
long-  ridcje  drawn,  from  Mr.  Bria;ham's  mni),  on  the  recent 
map  of  the  Government  Survey  (lettered  e  f,  (j  li).  The  ridges 
are  not  put  as  far  from  the  east  wall  of  tlie  crater  as  on 
Brigham's  map,  but  are  made  to  accord  with  the  statement  of 
both  Lyman  and  Coan  (p.  78)  and  of  Brigham  also,  that  they 
followed  the  course  of  the  lower-pit  wall  of  1840  a  little 
inside  of  its  position,  over  tlie  site  of  the  original  talus,  — 
Wilkes's  position  of  the  wall  being  adopted  except  for  a 
short  distance  near  e.  Halema'uma'u,  as  the  dotted  line 
inside  of  the  basin  of  the  Government  map  shows,  was  small 


140  VOLCANIC   ACTION. 

in   1864-1865,  it  being  only  one  thousand  feet  in  diameter 
and  but  little  raised  above  the  level  of  the  liquid  lavas. 

Mr.  Brigham's  map  shows  also  the  positions  of  active  lava- 
lakes  in  1864  or  1865  (lettered  i,  k,  I,  m)  ;  and  the  interest- 
ing fact  is  to  be  noted,  on  Plate  IX.,  that  two  of  them,  to 
the  northwest  (/,  k)  lie  at  the  edge  of  the  Mack  ledge,  while 
/,  m  are  a  little  back  of  it,  but  in  a  line  with  ?*,  k. 

The  long  curving  line  of  deep  fissures  and  fault-plane, 
already  referred  to  as  marking  the  outline  of  the  Halema'u- 
ma'u  region,  is  seen  on  Plate  IX.,  at  a  h,  not  to  be  concen- 
tric with  the  Halema'uma'u  basin  of  either  Brigham's  map  or 
of  the  recent  map,  but  to  that  of  Halema'uma'u  j^lfc^  the  New 
Lake  region  of  1884  to  1887.  Thus  in  1865,  when  Hale- 
ma'uma'u appeared  as  a  small  basin  one  thousand  feet  broad 
(not  half  its  existing  breadth),  the  fissure  indicated  the  pres- 
ence of  deep-seated  conditions  as  to  the  fires  and  forces  that 
finally  ultimated  in  its  extension  over  the  New  Lake  area. 
And  the  expression  of  this  fact  in  1865  was  doubled  by  a 
second  concentric  fissure  five  hundred  feet  farther  north 
(Plate  IX.,  c  d).  Further,  four  of  the  cones  mapped  by 
Brigham  in  the  vicinity  of  Halema'uma'u  in  1865  {p,  q,  r,  s, 
on  Plate  IX.)  are  inside  of  the  existing  Halema'uma'u  basin ; 
and  one  of  the  others  (o)  is  near  the  north  border,  and  an- 
other (/)  is  close  by  the  east  side  of  New  Lake. 

On  Mr.  Brigham  s  map,  the  position  is  given  of  a  very 
large  loose  block  of  lava,  which  is  shown  at  iv,  on  Plate  IX. 
It  lies,  as  is  seen,  in  the  northwest  part  of  the  crater,  and  is 
over  the  lower  edo:e  of  v^liat  in  1840  was  an  inclined  but  even 
lava-plane  to  the  bottom,  that  had  been  made  in  1840  by  an 
()hli([uo  down-plunge,  carrying  the  inner  side  of  the  great 
mass  down  and  leaving  the  other,  that  against  the  black 
ledge,  on  a  level  with  the  ledge,  with  a  broad  fissure  between. 
This  sloping  way  from  the  ledge  to  the  lower  floor  is  men- 
tioned on  page  70,  The  block  probably  slid  down  the  slope 
to  its   bottom.     But   in  the    lifting   again  of    the    obliquely 


PLATE  IX 


with  additionii  rrom  the  Uapx  of  Oipt.  Wllkm  tud 
W.  T.  Brigbtm. 


^  ->St^j  tli^fla'Jitt,  C  ■ 


PROGKESSIVE   CHANGES   IN   KILAUEA.  141 

subsided  mass,  as  the  Hour  was  raised  and  Lyman's  ridge  was 
made,  this  loose  block  was  lifted.  The  lift  along  that  part  of 
the  crater,  which  was  already  completed  in  1846,  consisted 
in  the  restoring  of  the  half-engulfed  mass  with  the  lava- 
block  on  its  surface,  to  its  former  horizontal  position ;  and 
this  was  the  position  it  had  when  Mr.  Brigham's  map  and 
observations  were  made. 

It  is  interesting  to  note  thus  how  the  1864-1865  condition 
of  Kilauea  grew  out  of  that  of  1840,  and  foreshadowed  that 
of  1887.  It  is  worthy  of  consideration,  also,  that  just  as  the 
fault-plane  a  h  is  concentric  with  the  Halema'uma'u  basin 
plus  New^  Lake,  so  the  far  greater  Kilauea  fault-planes,  two 
thousand  to  five  thousand  feet  north  and  northeast  of  the 
crater,  are  concentric,  not  with  Kilauea,  but  with  Kilauea 
plus  Kilauea-iki. 

II.     DYNAMICAL   CONCLUSIONS. 

General  Cycle  of  Movement  hi  Kilauea.  —  The  history  of 
Kilauea,  through  all  its  course  since  1823,  illustrates  the  fact 
that  the  cycle  of  movement  of  the  volcano  is  simply:  (1)  a 
rising  in  level  of  the  liquid  lavas  and  of  the  bottom  of 
the  crater ;  (2)  a  discharge  of  the  accumulated  lavas  down  to 
some  level  in  the  conduit  determined  by  the  outbreak  ;  (3)  a 
down-plunge  of  more  or  less  of  the  floor  of  the  region  under- 
mined by  the  discharge.  Then  follows  another  cycle  :  a  rising 
again,  commencing  at  the  level  of  the  lavas  left  in  the  con- 
duit, —  that  is,  the  lavas  of  the  lava-column,  —  which  rising 
continues  until  the  augmenting  forces,  from  one  source  or 
another,  are  sufficient  for  another  outbreak. 

In  1832  the  conditions  were  ready  for  a  discharge  when  the 
lavas  had  risen  until  they  were  within  seven  or  eight  hundred 
feet  of  the  top  ;  in  1840,  when  within  six  hundred  and  fifty 
feet  ;  in  1868,  when  within  five  or  six  hundred  ;  in  1886, 
when   within    three    hundred    and    fifty  feet.     The   greater 


142  VOLCANIC   ACTION. 

height  of  recent  time  may  seem  to  show  that  the  mountain 
has  become  stronger,  or  better  able  to  resist  the  augmenting 
forces.  But  it  also  may  show  a  less  amount  of  force  at  work. 
In  1823,  1832,  and  1840  the  down-plunge  affected  a  large 
part  of  the  whole  floor  of  the  crater,  which  proves  not  only 
the  vastness  of  the  discharges,  but  also  indicates  active  lava 
through  as  large  a  part  of  the  whole  area  preceding  the  dis- 
charge, while  in  1886  the  down- plunge  and  the  active  fires 
in  view  were  confined  to  Halema'uma'u  and  its  vicinity.  It 
w^as  not  in  earlier  time,  therefore,  the  greater  weakness  of 
the  mountain,  but  probably  the  greater  power  of  the  volcanic 
forces. 

The  broad  low-angled  cone  whicli  the  volcano  tends  to 
make,  has  a  great  breadth  of  stratified  lavas  to  withstand 
rupturing  forces.  How  great  may  easily  be  calculated  by 
comparing  a  cone  of  5°  to  8°  with  one  of  30°,  the  latter  the 
average  angle  of  the  greater  volcanic  mountains  of  western 
America  ;  and  this  suggests  important  differences  in  the  re- 
sults of  volcanic  action  independent  of  those  consequent  on 
the  possible  prevalence  of  cinder-ejections  in  the  latter. 
Somehow  or  other  Mount  Loa  breaks  easily  —  very  easily,  its 
quiet  methods  say  —  and  it  seems  to  be  because  such  rocks, 
however  thick,  can  offer  but  feeble  resistance  to  rupturing 
volcanic  agencies. 

In  the  discussion  beyond  of  the  operations  going  on  and  of 
their  causes,  I  speak  (1)  of  Kilauea  as  a  Basalt-volcano,  the 
basis  of  its  peculiarities  ;  (2)  of  the  size  of  the  Kilauea  con- 
duit ;  (3)  of  the  ordinary  work  of  the  volcano.  The  origin 
of  the  eruptions  of  Kilauea  is  considered  in  connection  with 
that  of  the  Mount  Loa  eruptions. 

1.     Kilauea  a  Basalt-volcano. 

The  Mobility  of  the  Lavas.  —  The  phenomena  of  Kilauea 
are  largely  due  to  the  fact  that  it  is  a  basalt-volcano  in  its 


KILAUEA  A  BASALT- VOLCANO.  143 

normal  state.  By  this  I  mean,  first,  that  the  rock-material 
is  doleryte  or  basalt,  and  secondly,  that  the  heat  is  sutlicient 
for  the  perfect  mobility  of  the  lavas,  and  therefore  for  the 
fullest  and  freest  action  of  such  a  volcano.  It  is  essentially 
perfect  mobility,  although  there  is  not  the  fusion  of  all  of  its 
minor  ingredients,  that  is,  of  its  chrysolite  and  magnetite. 
This  is  manifested  by  the  lavas,  whether  they  are  in  ebulli- 
tion over  the  Great  Lake,  throwing  up  jets  twenty  to  forty 
feet  high,  throughout  an  area  of  a  million  square  feet  or 
more,  or  when  only  splashing  about  the  liquid  rock  and  dash- 
ing up  spray  of  lava-drops  from  areas  of  a  few  square  yards. 
There  is  in  both  conditions  the  same  free  movement,  almost 
like  that  of  water,  and  suggesting  to  the  observer  no 
thought  of  viscidity.  Of  the  two  conditions  just  mentioned, 
the  former  was  that  of  November,  1840  ;  the  latter  that 
of  August,  1887,  and  of  the  larger  part  of  intermediate 
time. 

This  mobility  is  dependent  largely  on  the  fusibility  of 
the  chief  constituent  minerals  of  the  lava.  Trachyte  and 
rhyolyte  are  the  least  fusible  of  igneous  rocks,  because  the 
constituent  feldspar,  orthoclase,  is  the  least  fusible  of  the 
feldspars ;  and  basalt  or  doleryte  is  one  of  the  most  fusible, 
because  the  feldspar  present,  labradorite,  is  of  easy  fusibility, 
and  it  is  combined  in  the  rock  with  the  still  more  fusible 
augite  or  pyroxene. 

The  degree  of  mobility  is  dependent  also  on  temperature. 
It  is  probable  that  at  the  temperature  of  fusion,  or  better  a 
little  above  it,  all  the  feldspars,  the  least  and  the  most  fusible, 
are  nearly  alike  in  molnlity.  But  the  lower  the  degree  of 
fusibility  the  less  likely  is  the  heat  to  be  deficient,  or  below 
that  required  for  complete  fusion  and  mobility  ;  and  here 
comes  in  the  great  difference  among  them  as  regards  lavas 
and  volcanoes. 

The  basalt-volcano  has  special  advantage  over  all  others  in 
this  respect,  as  the  copious  Mount  Loa  lava-streams  and  the 


144  VOLCANIC   ACTION. 

immense  basaltic  outflows  of  other  regions  exemplify.  In 
Hawaii  the  heat  required  for  the  existing  mobility  is  no 
greater  than  the  deep-seated  conditions  below  the  mountain 
can  keep  supplied,  in  spite  of  cooling  agencies  from  cold  rocks, 
subterranean  waters,  and  the  air  ;  it  is  no  greater  than  it 
can  continue  to  supply  for  more  than  half  a  century,  as  tlie 
records  have  shown  ;  and  supply  freely  to  the  top  of  a  con- 
duit three  thousand  to  thirty-five  hundred  feet  above  the 
sea-level,  and  even  to  the  top  of  another  conduit  but  twenty 
miles  off,  rising  to  a  height  of  thirteen  thousand  feet  above 
the  sea-level.  The  temperature  needed  for  this  mobility,  judg- 
ing from  published  facts,  is  between  2000°  F.  and  2500°  F. 
The  fusing  temperature  of  augite  and  labradorite  has  not 
yet  been  determined.  We  are  certain  that  a  white  heat 
exists  in  the  lava  within  a  few  inches  of  the  surface  ;  for  the 
play  of  jets  in  a  lava-lake  makes  a  dazzling  network  of  white 
lightning-like  lines  over  the  surface  ;  and  white  heat  is  equiv- 
alent to  about  2400°  F.  Considering;  the  heig-ht  of  Mount 
Loa  and  the  greatness  of  its  eruptions,  and  the  vastness  of 
basaltic  outflows  over  the  globe,  we  may  reasonably  assume 
that  the  temperature  needed  for  the  normal  basalt-volcano 
has  long  been,  and  is  now,  easy  of  supply  by  the  earth  for 
almost  any  volcanic  region  ;  and  that  the  difficulty  the  earth 
has  in  supplying  the  higher  heat,  for  equal  mobility  in  a 
trachyte  or  rhyolyte  volcano,  is  the  occasion  of  the  semi- 
lapidified,  pasty  condition  of  their  outflowing  lavas. 

Even  if  the  higher  temperature  required  for  orthoclase 
lavas  were  always  present  quite  to  the  surface  in  the  volcano, 
the  ordinary  cooling  influences  of  cold  rocks  and  subterranean 
waters  and  air  would  be  sure  to  bring  out,  in  some  degree,  on 
a  globe  having  existing  climatal  conditions,  the  character- 
istics of  the  several  kinds  of  volcanoes  designated. 

It  cannot  be  affirmed  that  this  higher  heat  required  for  the 
complete  fusion  of  trachyte  or  rhyolyte  is  wanting  at  con- 
venient depths  below ;  for  it  has  been  manifested  in  the  out- 


KILAUEA   A   BASALT-VOLCANO.  145 

pouring  of  vast  floods  of  these  rocks  through  opened  fissures, 
many  examples  of  which  over  the  Great  Basin  are  mentioned 
in  King's  "Systematic  Geology"  of  the  Fortieth  Parallel. 
But  in  the  volcano,  whose  work,  after  an  initial  outflow,  is 
carried  forward  by  periodical  ejections,  and  requires  for  long- 
periods  a  continued  supply  of  great  heat,  the  more  or  less 
granulated  or  pasty  condition  of  the  outflowing  orthoclase- 
bearing  lava-streams  is  the  usual  one.  Consequentlv,  wlien 
a  volcano  changes  its  lavas  from  the  less  fusible  to  the 
more  fusible,  as  sometimes  has  happened,  some  change  in 
the  features  of  the  volcano  should  be  looked  for,  except 
perhaps  when  the  change  occurs  directly  after  the  initial 
discharge. 

Here  the  question  suggests  itself  whether  the  temperature 
existing  at  depths  below  may  not  be  one  of  the  conditions 
that  determine  whether  the  discharged  lavas  shall  be  of  the 
less  fusible  or  the  more  fusible  kind. 

But  a  hasaU-\o\ccii'io  also  niay  fail  to  have  heat  enough  for 
perfect  fusion,  and  hence  may  have  partially  lapidified  or 
pasty  lavas,  and  thus  be  made  to  exhibit  some  of  the  char- 
acteristics of  the  other  kinds  of  volcanoes.  This  condition 
may  result  from  three  causes :  (1)  A  decline  in  the  supply  of 
heat  of  the  conduit,  as  when  the  partial  or  complete  extinc- 
tion of  the  volcano  is  approaching;  (2)  When  the  lava  is  dis- 
charged by  lateral  openings  or  fissures,  in  which  case  the 
lateral  duct  of  lava  may  not  be  large  enough  to  resist  com- 
pletely the  cooling  agencies  about  it  ;  (3)  The  sudden  en- 
trance of  a  large  body  of  water  into  the  conduit. 

The  effects  from  the  first  of  these  conditions  —  declining 
heat  connected  with  approaching  extinction  —  are  strikingly 
exemplified  in  two  great  volcanic  mountains  of  the  Hawaiian 
Islands,  Mount  Kea  on  Hawaii,  and  Haleakala  on  Maui. 
Those  of  the  second,  in  which  the  ejections  are  from  lateral 
openings,  are  abundantly  illustrated  in  the  cinder  and  tufa 
cones  of  the  islands,  and  also  in   widespread   cinder  or  ash 

19 


146  VOLCANIC   ACTION. 

deposits  through  the  driftmg  of  the  ejected  material  by  the 
winds.  The  third,  a  sudden  incursion  of  waters  through  an 
opened  fissure,  if  a  possibility,  should  both  lower  the  temper- 
ature and  produce  violent  projectile  results ;  and  even  Kilauea 
bears  evidence  of  at  least  one  eruption  of  great  magnitude 
which  was  thus  catastrophically  produced,  —  that  of  1789; 
for  the  region  bordering  the  crater  on  all  its  sides,  and  to  a 
distance  of  ten  or  fifteen  miles  to  the  southwest,  is  covered 
with  the  ejected  stones  or  bowlders,  scoria,  and  ashes  of  such 
an  eruption. 

Besides  the  influence  of  degree  of  fusibility  of  the  lavas  on 
the  features  and  action  of  volcanoes,  there  is  also  some  effect 
from  their  specific  gravity,  which  varies  much  with  the  vari- 
ations in  the  amount  present  of  either  of  the  iron-bearing 
minerals  augite,  hornblende,  chrysolite,  and  some  other  re- 
lated species.  But  little  or  no  importance  is  attributable  to 
the  amount  of  silica  present,  or  the  acidic  or  hasic  character 
of  the  feldspar  or  rock.  The  distinction  of  basic  and  acidic, 
of  great  interest  mineralogically  and  chemically,  has  in 
fact  little  importance  in  the  science  of  volcanoes,  while  that 
of  fusibility  is  fundamental.  The  most  basic  of  all  the  feld- 
spars, anorthite,  is  as  little  fusible  as  the  most  "  acidic " 
of  feldspars,  orthoclase,  and  more  so  than  the  equally 
''  acidic  "  albite.^  It  is  plain,  therefore,  that  the  quality  of 
being  heme  does  not  explain  the  fusibility  of  the  lavas. 
Neither  does  it  explain  any  other  of  the  physical  character- 
istics on  which  tlie  peculiarities  of  the  volcano  depend. 

It  is  also  true  that  the  chrysolite  (or  olivine),  the  ultra- 
basic  constituent  of  the  lavas,  has  little  influence  on  their 
physical  characters  except  through  its  higli  specific  gravity, 
which  is  about  o-o  to  3-4.  The  mineral  chrysolite  is  infusible, 
and  cannot  increase  the  mobility  of  the  lavas  ;  and  there  is 

*  In  mv  "  Manual  of  Mineralogy  and  Petrography,"  page  436, 1  point  out  further 
that  the  distinction  of  alkali-hearing  and  not  alkali-hearing  among  the  silicates  is 
of  much  more  geological  importance  than  the  much  used  one  of  acidic  and  basic. 


KILAUEA   A   BASALT-VOLCANO.  147 

fomuioiily  not  enough  of  it  in  the  Kikuea  rocks  to  diminish 
the  mobility  ;  for  ;i  hirge  part  of  the  lava  contains  less  than 
five  per  cent,  and  much  of  it  less  than  one  per  cent.  Chryso- 
lite is  uUra-basic ;  but  this  qnality  has  little  volcanic  im- 
portance. It  is  not  the  little  amount  of  silica  in  it  that  i,s 
influential  volcanically,  but  the  much  iron.  The  presence  of 
much  chrysolite  does  not  even  determine  the  distril^ution 
of  the  lavas  of  Mount  Loa  ;  for,  as  shown  beyond  (p.  324),  no 
Hawaiian  lavas  contain  more  chrysolite  or  have  higher  spe- 
cific gravity  than  some  of  those  of  recent  ejection  at  the 
summit  of  Mount  Loa. 

Eruptive  Characteristics  of  a  Basalt-volcano.  —  The  obvious 
results  of  superior  mobility  and  density  in  lavas  are,  as  in 
other  liquids  :  — 

First,  greater  velocity  on  like  slopes,  and  thus  an  easier 
.flow,  with  less  liability  to  be  impeded  by  obstructions;  a 
lower  mininuun  angle  of  flow,  and  consequently  a  less  angle 
of  slope  for  the  lava- cones. 

Secondly,  the  vapors  ascending  through  the  liquid  lava 
encounter  comparatively  feeble  resistance,  and  hence  the 
expansive  force  required  for  escape  of  bubbles  through  the 
lava  to  the  surface  is  feeble ;  and  so  also  are  the  projectile 
effects  due  to  the  explosion  of  the  bubljles.  Hence  the  pro- 
jected masses  commonly  go  to  a  small  height  —  it  may  be 
but  a  few  yards  —  and  fall  Ijack  before  cooling,  instead  of 
reaching  to  a  height  that  involves  their  cooling  and  solidifi- 
cation in  the  air  and  the  making  thus  of  cooled  fragments  of 
lava  or  scoria,  called  cinders  and  volcanic  ashes. 

The  projectile  proc(^ss  in  the  basalt-volcano,  as  long  as  it  is 
in  its  normal  stage,  makes,  as  stated  on  page  17,  not  cinder- 
cones,  but  driblet-cones,  fifteen  to  sixty  feet  high,  out  of 
the  projected  masses,  the  falling  driblets  becoming  plastered 
together  about  the  small  places  of  ejection.  Among  the  pro- 
jectile results  of  volcanoes  driblet-cones  are  at  one  extremity 
of  a  series,  and  cinder  or  tufa  cones,  many  hundreds  of  feet 


148  VOLCANIC   ACTION. 

liisch,  at  tiie  other.  A  cinder-cone  of  a  thousand  feet  m 
height  has  fifteen  to  twenty  thousand  times  the  bulk  of  any 
driblet-cone.  The  process  is  one  ;  but  the  result  varies  with 
the  mobility  and  fusibility  of  the  lavas. 

Further  :  in  the  great  lava-cone  of  a  basalt-volcano  in  its 
normal  stage,  cinder  or  tufa  deposits  rarely  alternate  with 
the  large  lava-streams,  while  they  commonly  alternate  in 
other  kinds  of  volcanoes. 

Further :  cinder-cones  and  beds  of  volcanic  ashes  may 
form  about  a  basalt-volcano,  as  already  explained,  whenever 
the  condition  of  insufficient  heat  is  in  any  wa}^  occasioned. 

The  above  views  as  to  the  characteristics  of  a  normal 
basalt-volcano  are  sustained  by  the  facts  from  the  volcanic 
mountains  of  all  the  Hawaiian  Islands. 

In  the  first  place,  the  slopes  are  not  only  the  lowest  pos- 
sible, usually  from  less  than  1°  to  10°.  but  continuous  flows 
of  10"  to  90"*  occur.  The  author  has  seen  many  of  them 
descending  as  unbroken  streams  vertical  precipices  on  south- 
ern and  western  Hawaii.  The  example  shown  in  Plate  XL 
is  small  compared  with  many  about  Mount  Loa. 

Again  :  the  alternation  of  the  lava-streams  of  the  great 
volcanoes  with  deposits  of  volcanic  sand,  scoria,  or  stones  that 
were  ejected  from  the  great  craters,  is  of  rare  occurrence  ;  and 
such  deposits  make  only  thin  beds  of  the  kind  whenever  they 
occur.  In  such  examinations  as  the  author  was  able  to  make 
of  the  walls  of  Kilauea  and  Haleakala  and  of  the  precipices 
and  Ijluffs  of  Oahu  he  did  not  succeed  in  finding  cinder  or 
tufa  deposits  among  the  lavas  of  the  body  of  the  mountain, 
thouo^h  a  common  feature  wherever  lateral  cones  have  been 
thrown  up.  The  walls  of  Kilauea  are  stratified  from  top 
to  bottom,  but  with  lava-streams,  and  comparatively  thin 
streams.  No  evidence  was  found  in  the  examinations  of  its 
walls  of  any  intervening  stratum  or  bed  of  scoria,  tufa,  or 
stones  like  that  wdiich  now  covers  its  border.  This  testi- 
mony is  not  conclusive  as  to  the  alxsence  of  such   projectile 


KILAUEA   A   BASALT-VOLCANO.  149 

eruptions  in  former  times  ;  for  thin  beds  of  scoria  or  sand 
like  that  just  referred  to  —  its  thickness  is  only  twenty-five 
to  thirty  feet  —  might  be  fused  and  annexed  to  the  succeed- 
inti-  lava-flow.  But  the  evidence  against  great  tufa-deposits 
amouLT  the  Hawaiian  lavas,  excepting  those  from  lateral 
ejections,  is  sufficient. 

Ou  the  island  of  Maui  no  such  beds  of  projectile 
origin  were  found  in  the  walls  of  Haleakala,  or  in  those  of 
Wailuku  valley,  —  the  probable  crater  cavity  of  western 
Maui.  On  Oahu  the  pitch  of  the  layers  of  lava  along  the 
Manoa  and  Nuuanu  valleys  is  only  1°  to  3° ;  and  in  the 
precipices  and  bluffs  which  Ijound  them  I  saw  no  layer  of 
tufa.  The  thick  tufa-deposits  are  confined  to  the  beds  of 
cinder  and  tufa  cones,  and  these  are  common. 

This  point  needs  investigation  ;  for  the  existence  of  even 
thin  tufa-beds  in  alternation  with  the  lava-beds  of  the  great 
volcanoes  of  the  islands  may  still  be  true,  and  such  facts 
would  have  much  interest.  The  author  observed  beds  of 
conglomerate  on  Oahu  and  Kaui,  but  all  may  have  come 
from  lateral  cones. 

The  Crater  of  a  Basalt-volcano  is  the  same  in  Origin.  His- 
tory, and  Functions  as  those  of  Volcanoes  of  other  Kinds,  hut 
differs  iisucdh/  in  Form.  —  The  crater  of  a  great  volcano 
probably  has  always  its  beginning  in  a  great  discharging 
fissure,  or  in  the  crossing  of  two  fissures  ;  and  it  continues 
open  until  a  temporary  or  final  decline  of  volcanic  action, 
whatever  the  kind  of  volcano.  It  continues  open,  (1)  because 
of  the  fixed  position  of  the  lava-column,  (2)  because  of  the 
conduit-work  going  on  through  it  in  the  discharge  of  vapors 
and  lavas,  and  (3)  because  of  tlie  down-plunges  in  the  crater 
consequent  on  the  undermining  which  tlie  discharge  of  the 
conduit  occasions.  The  open  end  of  a  deep-reaching  lava- 
column  determines  thus,  by  its  discharges  and  the  subsequent 
underminings,  the  existence  of  the  crater ;  and  the  crater,  by 
the  work  done  within  and  about  it,  makes  the  volcanic  cone. 


150  VOLCANIC   ACTION. 

This  appears  to  be  the  order  of  rank  or  importance  in  the 
phenomena,  —  the  crater  begins  in  the  opened  hssure,  and  is 
the  indicator  and  future  builder  of  the  cone.  In  the  history 
of  the  volcano  the  era  of  summit  outflows  niciy  pass,  and 
only  lateral  discharges  take  place  ;  and  still  the  discharge  of 
vapors  from  the  lava-conduit  and  the  accompanying  move- 
ments in  the  lavas,  together  with  the  down-plunges  in  the  cra- 
ter following  the  discharges,  will  keep  the  crater  or  portions 
of  it  in  continued  existence,  and  the  work  of  eruption  or  out- 
flow, if  subaerial,  will  be  still  adding  to  and  shaping  the  cone. 

This  is  the  present  stage  of  Kilauea  and  Mount  Loa  ;  and 
these  are  the  results  as  they  exemplify  them.  The  action, 
functions,  and  processes  are  the  same  whether  the  lavas  fill 
up  to  the  summit  before  outflowing,  or  become  discharged  at 
a  lower  level  by  an  opened  fissure. 

Examples  in  the  Hawaiian  Islands  teach  also  that  vol- 
canoes may  end  with  an  open  crater  over  two  thousand  feet 
deep,  like  Haleakala,  a  cone  ten  thousand  feet  high,  or  with 
a  filled  crater,  as  in  the  case  of  Mount  Kea,  thirteen  thousand 
eight  hundred  feet  high. 

The  preceding  remarks  about  the  permanence  of  craters 
apply  to  other  kinds  of  volcanoes  as  well  as  the  basaltic ;  but 
in  the  form  of  the  crater  the  basalt-volcano  has  peculiarities, 
owing  to  the  mobility  of  the  lavas  and  the  paucity  of  cinder 
discharges.  The  ordinary  crater  of  the  basalt-volcano  is  pit- 
like, with  the  walls  often  nearly  vertical,  and  the  floor  may 
be  a  great  nearly  level  plane  of  solid  lavas.  The  liquid  ma- 
terial of  the  extremity  of  a  conduit  works  outward  from  the 
hotter  centre,  through  the  fusing  heat  and  the  boiling  and 
other  caldron-like  movements  ;  and  hence,  where  the  mo- 
bility favors  freedom  of  action  in  these  respects,  it  tends  to 
give  the  basin  or  crater  a  nearly  circular  form,  with  steep 
sides.  Besides,  when  the  discharge  takes  place  there  is  usu- 
ally a  fall  of  the  walls,  which  is  still  another  reason  for 
vertical  sides  and  the  pit-like  form. 


KILAUEA   LAVA-COLUMN.  15 1 

The  small  lava-lakes  of  Kilauea,  and  the  Great  South  Lake 
also,  after  a  discharge  (or  an  eruption,  as  it  is  usually  called), 
are  literally  pit-craters.  Such  was  the  condition  of  the  Great 
Lake  after  the  eruption  of  1886.  They  all  illustrate  how  the 
great  pit-crater,  Kihxuea,  was  made.  The  "lower  pits"  of 
1823,  1833,  1840,  are  other  examples. 

Such  pit-craters  are  normally  circular ;  but  where  there 
is  a  large  fissure  beneath  the  crater  they  may  be  much 
elongated. 

From  the  considerations  which  have  been  presented  we  see 
why  the  volcanic  mountains  of  the  Hawaiian  Islands,  with 
slopes  rarely  exceeding  10°  in  angle,  differ  so  widely  from  the 
great  andesyte  cones  of  western  North  America,  with  their 
high  slopes  of  28°  to  35^.  We  see  that  the  fact  of  being 
basalt-made  means  much  in  a  volcano  ;  that  it  affects  pro- 
foundly all  the  movements  and  the  results  of  those  move- 
ments, as  well  as  the  shapes  of  the  mountains  and  of  their 
craters. 

2.    Size  of  the  Kilauea  Lava-column. 

To  appreciate  the  power  at  work  in  Kilauea  and  under- 
stand its  action,  we  should  know,  if  possible,  the  diameter  of 
the  lava-column  beneath  ;  and  for  this  we  have  to  look  to  its 
condition  both  in  times  of  eruption  and  in  periods  of  relative 
quiet. 

In  view  of  the  greatness  of  the  discharge  in  1823,  —  so 
undermining,  owing  to  its  extent,  as  to  drop  abruptly  to  a 
depth  of  some  hundreds  of  feet  the  floor  of  the  crater,  leaving 
only  a  narrow  shelf  along  the  sides,  —  we  reasonably  con- 
clude that  at  that  time  the  lava-column  beneath  the  floor 
was  of  as  large  area  as  the  Kilauea  pit  itself,  —  or  nearly 
seven  and  a  half  miles  in  circuit.  We  may  also  infer  that, 
immediately  before  the  discharge,  wherever  there  was  a  lava- 
lake,  the  liquid  top  of  the  column  was  up  to  the  floor  of  the 
crater,  and  elsewhere  not  far  below  it.     The  inference  is  sim- 


152  VOLCANIC   ACTION 

ilar  from  the  eruptions  of  1832  and  1840.  When  the  floor 
of  the  pit  fell  at  the  discharge  in  1840  it  was  not  thrown 
into  hills  and  ridges,  as  it  might  have  been  had  it  dropped 
down  its  four  hundred  feet  to  solid  rock  in  consequence  of  a 
lateral  discharge  of  the  lavas  beneath  ;  on  the  contrary,"  it 
kept  its  flat  surface,  thus  showing  that  it  probably  followed 
down  a  liquid  mass,  that  of  the  subsiding  column  of  lava. 

But  it  is  probable  that  the  conduit  had  then,  and  has  still, 
a  larger  area  than  that  of  the  Kilauea  crater. 

At  the  eruption  of  March,  1886,  when  the  emptying  of 
Halema'uma'u  and  its  bordering  lake  at  the  south  end  of 
Kilauea  was  all  the  visible  evidence  of  discharge,  the  sol- 
fatara  at  the  north  end,  two  and  a  half  miles  from  Hale- 
ma'ma'u,  showed  sympathy  with  the  movement ;  for  the 
escape  of  vapors  from  its  fissures  suddenly  ceased,  as  if  the 
source  of  the  hot  vapors  had  participated  in  the  ebb,  while  a 
few  hours  before  the  discharge  the  vapors  were  unusually 
hot,  so  as  to  prevent  the  use  of  the  bath-house.  Thus,  even 
now,  during  a  comparatively  small  discharge,  we  have  evi- 
dence that  the  two  distant  extremities  of  the  crater  are  un- 
derlaid by  intercommunicating  liquid  lava.  Mr.  Brigham 
speaks  of  hearing  in  1880,  when  at  the  vapor  bath-house  in 
the  solfatara,  sounds  from  below,  —  ''rumbling  and  hard  noises, 
totally  unlike  the  soft  hissing  or  sputtering  of  steam,"  ^  —  a 
fact  that  seems  to  favor  the  above  conclusion.  Further, 
throuo;h  all  known  time,  as  now,  several  of  the  fissures  in 
the  solfatara  region  have  discharged,  besides  steam,  sulphur- 
ous acid  freely  ;  and  this  is  probably  from  liquid  lavas. 

The  summit  of  the  conduit  must,  therefore,  be  even  larger 
than  all  Kilauea.  To  this  may  perhaps  be  added  the  border- 
ing; reg-ion  of  fi.ssures  and  abrunt  subsidences  ;  for  subsidences 
or  down-plunges  indicate  imder mining ;  and  undermining 
here  means  the  removal  of  liquid  material  from  beneath. 
With  this  addition  to  the  limits,  the  width  is  sixteen  thou- 

^  American  Journal  of  Science,  1887,  .\xxiv.  27. 


IN    THE    ORDINARY    WORK   OF   KILAUEA.  153 

sand  feet,  and  the  length  as  much,  plus  a  mile  or  more  to  the 
southwest,  where  the  fissures  of  1868,  if  not  also  of  earlier 
date,  are  giving  off  hot  vajDors  abundantly. 

But  while  this  may  be  the  area  of  the  upper  extremity  of 
the  lava-column,  its  top  surface  is  not  a  level  plane,  as  the 
condition  of  the  region  over  it  indicates.  A  small  part  of  it 
at  all  times  (with  short  exceptions  after  an  eruption)  has  ex- 
tended up  to  the  surface  in  Halema'uma'u,  and  occasionally 
in  other  lava-lakes  during  times  of  special  activity ;  for  each 
such  lake,  however  small,  nuist  have  its  separate  conduit 
reaching  down  to  the  general  liquid  mass  and  giving  upward 
passage  to  the  working  vapors.  We  learn,  hence,  that  what- 
ever the  number  of  these  large  and  small  conduits,  they  may 
act  —  that  is,  overflow,  and  rise  and  fall  in  level  —  indepen- 
dently, because  the  size  is  very  small  compared  with  that  of 
the  reservoir  from  which  they  rise. 

3.    Ordinary   Work   of   Kilauea. 

By  the  ordinary  work  of  Kilauea  is  here  meant  the  work 
which  is  carried  on  between  epochs  of  eruption.  A  large 
part  of  it  is  the  living  work  of  the  volcano,  the  regular 
daily  action,  never  joermanently  ceasing  except  with  the 
decline  and  extinction  or  withdrawal  of  the  fires.  The 
deep-reaching  column  of  lavas,  which  is  the  source  of  the 
heat  and  centre  of  this  living  activity,  owes  a  large  part 
of  its  power  to  act  the  volcano,  and  make  a  volcanic  moun- 
tain, to  the  presence  of  something  besides  heat  and  rocks. 
Vapors  are  ever  rising  and  escaping  from  the  conduit,  and 
though  lazy  in  the  clouds  above  where  their  work  has  come 
to  an  end,  they  carry  on  nearly  all  the  oi^dlnani  action  of 
a  crater,  even  that  of  greatest  brilliancy  and  loftiest  fiery 
projection,  as  well  as  the  gentler  play  of  the  fires.  But 
these  vapors  have  not  produced  the  great  eruptions  in 
Kilauea  smce  the   century  begun ;    they   occasion    only    its 

20 


154  VOLCANIC  ACTION 

quiet  or  lively  activity  in  periods  of  regular  work  between 
eruptions.  I  add  also,  lest  I  be  misunderstood,  tliat  tbe 
vapors  are  bad  for  fuel,  as  they  tend  to  put  the  fires  out, 
but  good   for   work.  * 

There  is  another  source  of  work,  perhaps  a  perpetual 
source  during  the  active  life  of  a  volcano  as  it  is  a  perpetual 
source  of  heat ;  namely,  the  ascensive  force  of  the  conduit 
lavas.  But,  unlike  the  vapors,  it  is  an  invisible  agency, 
slow  in  its  irresistible  movements.  What  are  its  limita- 
tions, and  what  its  source,  still  remain  undetermined. 

The  other  agencies  concerned  in  the  ordinary  work  have 
only  occasional  effects.  They  include  heat  in  work  outside 
of  the  conduit,  and  hydrostatic  and  other  working  methods 
of  gravitational  pressure. 

Tabulating  the  agencies,  they  are  as  follows  :  — 

A.  The  vapors. 

B.  The  ascensive  force  of  the  conduit  lavas. 

C.  Heat,  dis|)lacing,  disrupting,  fusing. 

D.  Hydrostatic  and  other  gravitational  pressure. 

All  these  agencies  do  their  work  around  the  lava-conduit, 
as  their  central  source  of  energy,  or  about  its  branches,  and 
therefore,  as  has  been  explained,  pericentrically. 

A.     THE   WORK    DONE   BY   VAPORS. 

Only  part  of  the  work  of  vapors  is  of  the  permanent  kind, 
carried  on,  as  above  described,  by  the  vapors  rising  through 
the  lavas  of  the  conduit.  Another  efficient  part,  but  most 
efficient  in  times  of  eruption,  is  dependent  on  vapors  gener- 
ated outside  of  the  conduit.  In  addition,  there  are  the 
chemical  effects  of  vapors.     The  work  includes :  — 

1.  The  effects  of  the  expansive  force  of  vapors  in  their  es- 
cape from  the  liquid  lavas :  projectile  action  and  its  results. 

2.  The  effects  of  the  expansive  force  of  vapors  within  the 
liquid  lavas  :   vesiculation  and  its  results. 


IN   THE   ORDINARY   WORK   OF   KILAUEA.  155 

3.  The  eli'ects  of  vapors  generated  outside  of  the  conduit  : 
fractures,  displacements,  etc. 

4.  The  chemical  action  of  vapors;  which  is  considered  in 
this  work  only  as  regards  certain  metamorphic  effects. 

1.    The   Vapors   concerned:   their   Kinds   and   .Sources. 

The  vapors  of  Kilauea  have  not  yet  been  made  a  subject 
of  special  investigation.  Still,  there  is  no  question  that  the 
chief  xcorhiwj  vapor  is  the  vapor  of  water ;  besides  which 
there  is  a  little  sulphur  gas,  and  probably  some  atmospheric 
air.  Investigations  elsewhere  have  establislied  the  fact  of 
the  vast  predominance  of  water-vapor  among  aerial  vol- 
canic products,  proving  that  less  than  one  part  in  one 
hundred  is  vapor  of  any  other  kind.  The  statement  of 
Mr.  J.  S.  Emerson  ^  that  on  the  west  n^argin  of  Halema'u- 
ma'u,  at  one  of  his  surveying  stations  in  April  of  1886,  to 
leeward  of  a  ''  smoke-jet,"  he  continued  his  work  ''  without 
regard  to  the  smoke  whicli  the  wind  carried  over  him  within 
a  few  feet  of  his  head,"  is  proof  that  the  air  held  little  sul- 
phurous acid. 

Mr.  Brigham  was  led  to  conclude,  from  his  seeing  so  little 
vapor  rising  from  the  Great  Lake  during  his  visit,  that 
too  much  influence  had  been  ascribed  by  others  to  water ; 
and  this  view  is  presented  also  by  Mr.  W.  L.  Green,  of 
Honolulu,  who  refers  part  of  the  movements  in  the  lake  to 
escaping  atmospheric  air ;  the  air  IxMug  supjjosed  to  be  car- 
ried down  by  the  splashing  and  jetting  lavas,  there  to  be- 
come the  source  of  the  splashing,  and  to  become  confined 
in  this  and  other  ways,  and  be  carried  deeper  for  other 
work.^  But  the  amount  of  vapor  escaping  from  a  lake  in 
times  of  moderate  activity,  when  it  is  mostly  crusted  over, 
is  very  small,  being  only  that  from  the  vesicles  (p.  166) 
and  breaking  bubbles  in  the  actively  liquid  portion  ;  and  in 

*  American  Journal  of  Science,  1887,  xxxiii.  90. 

2  Vestiges  of  the  Molten  Globe,  part  ii.,  8vo^  Honolulu,  1887. 


156  VOLCANIC   ACTION 

a  state  of  brilliant  action,  the  hot  air  above,  up  to  a  height 
where  the  temperature  is  diminished  from  that  of  the  liquid 
lavas  to  oU0°  ¥.,  will  dissolve  and  hold  invisible  nearly  five 
times  as  much  moisture  as  at  212" ;  up  to  440°,  sixteen 
times  as  much ;  and  to  44G°,  twenty-seven  times.  Tlie 
absence  of  vapors  over  a  flowing  lava-stream  is  made  evi- 
dence against  the  presence  of  water  ;  but  if  all  is  from  one 
source,  there  should  be  none  except  at  the  source. 

The  amount  of  sulphur  in  the  vapors,  and  its  condition  be- 
fore the  escape  from  the  lava,  whether  as  sulphur  vapor  sim- 
ply or  as  sulphurous  acid  (sulphur  dioxide),  are  questions  for 
the  future  investigator.  Pyrite,  or  some  iron  sulphide,  being 
its  probable  source,  I  add  that  I  have  detected  pyrite  in  the 
lava  of  a  dike  on  Oahu,  \mi  not  in  the  lavas  of  the  crater, 
where  we  should  hardly  expect  its  presence.  Chalcopyrite 
(copper  pyrites)  may  also  be  present,  as  stated  on  page  73. 
The  faintly  greenish  tint  of  the  flames  mentioned  on  pages 
88.  96,   119,   may  have   this  source. 

Carhonic  acid  has  not  been  observed  escaping  from  fuma- 
roles  aljout  any  part  of  the  Hawaiian  Islands,  and  no  frag- 
ments of  limestone  have  been  found  among  the  ejectamenta 
of  Kilauea  or  Mount  Loa.  The  volcanoes  stand  in  the  deep 
ocean,  and  the  conduit  nnist  come  up  through  old  lavas  for 
thousands  of  feet,  and  hence  carbonic  acid  is  only  a  pos- 
sible not  a  prolja1)le  product.  The  position  of  the  volcanic 
region  in  mid-ocean,  where  continental  geological  work 
has  most  probably  never  gone  forward,  makes  it  almost 
certain  that  there  is  none  above  the  level  of  the  ocean's 
bottom. 

The  presence  of  lujdrogen  among  the  escaping  vapors  re- 
mains to  be  determined.  The  pale  flames  seen  about  the 
Great  Lake  may  come  from  the  burning  of  escaping  hydro- 
gen or  of  sulphur  vapor  or  of  hydrogen  sulphide. 

The  source  of  the  ivater  or  moisture,  whence  comes  the 
chief  part  of  the  escaping  vapors,  is  probably  atmospheric. 


IN   THE    ORDINARY   WORK   OF   KILAUEA.  157 

On  this  point  the  arguments  appear  to  be  as  strong  now  as 
in  1840. 

Kilauea  is  situated,  like  Hilo,  in  a  region  of  ahnost  daily 
mists  or  rains,  and  if  approaching  Hilo  in  amount  of  precip- 
itation, as  is  probable,  over  one  hundred  inches  of  rain  fall  a 
year.  Tables  give  over  two  liundred  inches  some  years  for 
Hilo.  The  whole  becomes  subterranean,  except  what  is  lost 
by  evaporation  ;  for,  owing  to  the  cavernous  and  fissured 
rocks,  there  are  no  running  streams  over  the  eastern  or 
southeastern  slopes  of  the  island  south  of  the  Wailuku  River, 
which  comes  down  from  the  northwest  to  Hilo.  That  which 
falls  into  Kilauea  and  on  its  borders  gives  moisture  to  the 
many  steaming  fissures  ;  and  sometimes  it  makes  a  steaming 
area  of  the  whole.  But  this  part  has  very  little  to  do  with 
the  volcanic  action. 

Part  of  the  subterranean  water  follows  the  underground 
slopes  seaward,  as  shown  by  copious  springs  in  some  places 
near  the  shores,  and  takes  no  part  ordinarily  in  the  volcanic 
work.  But  another  part  must  descend  by  gravity  vertically, 
or  nearly  so,  and  keep  on  the  descent  far  below  the  sea-level. 
It  has  been  shown  on  a  former  page  (p.  125)  that  much 
the  greater  number  of  the  eruptions  have  occurred  in  the 
months  from  March  to  June,  and  this  appears  to  indicate  a 
dependence  of  the  action  to  some  extent  on  the  abundance 
of  precipitation.^ 

Moisture  may  be  gathered  also  from  all  moist  rocks  along 
the  course  of  the  conduit  in  the  depths  miles  below  the  reach 
of  superficial  waters,  as  suggested  by  different  writers  on  vol- 
canoes. But  any  dependence  on  the  amount  of  precipitation 
would  show  that  this  is  not  its  chief  source. 

Another  source  of  water  is  the  sea.     But  sea-water  could 


^  Tlii.s  view  with  regard  tf)  the  sources  of  the  waters  is  sustained  by  several 
writers.  It  is  well  presented,  with  fxplanations  at  len^i^th  as  to  the  water-line  in 
the  volcanic  mountains,  in  a  paper  »n  "  The  Agency  of  Water  in  Volcanic  Erup- 
tions," by  Prof.  .Joseph  Prestwich,  Proceedings  of  the  Royal  Society,  .\li.  117. 


158  VOLCANIC   ACTION 

not  ordinarily  gain  access  to  the  lava-column  except  at 
depths  much  below  the  sea-level,  on  account  of  the  abun- 
dance of  subterranean  island  waters  pressing  downward 
and  outward.  Further,  no  one  has  yet  reported  evidence 
of  the  presence  of  marine  salts,  or  chlorides,  beyond  mere 
traces,  among  the  saline  products  of  Kilauea  or  ^lount  Loa 
after  an  eruption. 

A  third  source  of  moisture  is  the  deep-seated  region  in  or 
beneath  the  crust  whence  the  lavas  come.  Of  this  we  know 
nothing.  The  fact  that  the  presence  of  such  moisture  below 
would  make  this  a  dangerous  earth  to  live  on  has  been  urged 
against  the  idea  of  such  a  soin"ce. 

Since  all  ordinary  action  in  Kihiuea,  and  also  in  Mount 
Loa,  is  of  the  quiet  non-seismic  kind,  the  introduction  of 
water  iuto  the  conduit  must  be  an  ordinary  and  a  quiet 
process,  not  one  of  sudden  intrusion  through  fissures.  Sud- 
den intrusions  may  sometimes  take  place  for  eruptive  effects, 
but  of  these  we  are  not  speaking.  The  facts  from  the  vesic- 
ulation  of  some  lava-flows  of  Mount  Loa,  brought  out  beyond 
(p.  166),  give  further  evidence  as  to  the  quiet  molecular  oc- 
clusion of  the  waters.  Moreover,  as  remarked  on  page  19, 
the  possibility  of  this  method  of  imbibition  appears  to  be 
demonstrated  by  Daubree's  experimental  work,  which  proves 
that  the  process  will  go  on  through  capillarity  or  molecular 
movement,  against  the  opposing  pressure  of  vapors  within.^ 
He  uses  the  fact  to  explain   the  origin   of  volcanic  vapors. 

2.    The  Effect  of  the  Expansive   Force  of  ^apors  in  their  Escape 
FROM  THE  Liquid  Lavas  :  Projectile  Action. 

All  the  lava-lakes  of  the  crater,  whether  one  alone  exists 
or  many,  and  the  smaller  vents  over  fires  that  are  concealed 

^  Geologie  Experimentale,  2  vols.  8vo,  Paris,  1879,  p.  235. 

The  temperature  of  the  liquid  lava  is  nearly  that  of  the  dissociation  tempera- 
ture of  water  —  1985°  F.  to  2370°  F.,  according  to  M.  H.  St.  Claire  Deville,  —  and 
higher  than  this  no  doubt  at  depths  below.  But  that  dissociation  takes  place 
within  the  conduit,  under  the  pressure  there  existing,  is  not  satisfiictorily  proved. 


IN   THE  ORDINARY   WORK   OF   KILAUEA.  159 

but  not  at  too  groat  depths,  send  forth  vapors,  which  in 
their  effort  to  escape  as  bubbles  through  a  resisting  me- 
dium, that  is,  the  lavas,  do  projectile  work.  The  vapors  thus 
produce  the  play  of  jets  over  lava-lakes  with  the  muffled 
sounds  and  tremor  of  ebullition  ;  and  also  the  splashing  and 
the  throwing  of  spray  from  open  fire-places  along  the  borders 
of  the  crusted  lakes.  They  dash  up  the  melted  fragments 
from  a  blow-hole  with  a  rush  and  roar  "  rivalling  sometimes 
a  thousand  engines,"  thus  introducing  the  coarser  effects  of 
gunnery  into  Kilauea.  They  make  the  thin  crust  of  the 
crusted  lake  to  heave  and  break,  press  into  rope-like  folds 
the  lava  along  the  red  fissures,  or  start  a  new  play  of  fiery 
jets,  high  or  low,  and  frequently  several  in  alternate  play; 
or  they  make  openings  and  push  out  a  flood  of  lava  ;  and 
occasionally,  when  rising  in  unwonted  volume,  they  make 
lava-fountains  of  unusual  heights  over  the  lakes,  with  at 
times    loud    detonations. 

The  projectile  force  required  to  throw  up  jets  of  lava  to 
the  heighV  which  they  ordinarily  have  in  times  of  brilliant 
activity,  thirty  feet  or  so,  is  even  less  than  a  calculation  from 
the  heiglit-,  diameter,  and  density  would  make  it,  because  the 
jets  before  they  reach  their  limit  usually  have  become  divided 
into  clots,  instead  of  remaining  a  continuous  stream. 

The  fact  that  the  throw  in  the  projectile  action  of  a  crater 
is  usually  vertical  is  well  shown  in  some  of  the  vertically 
columnar  forms  of  driblet-cones.  This  is  the  case  in  that 
of  the  figures  on  pages  71,  91,  in  which  the  column  was 
elongated  vertically,  although  a  result  of  successively  de- 
scending drops.  This  vertical  throw  —  due  to  the  fact  that 
the  top  of  the  bubble  is  the  weak,  and  therefore  the  explod- 
ing, spot  —  makes  the  projectile  action  good  for  throwing 
upward,  hut  not  good  for  a  destructive  homhardment  of  a 
crater's  vmlls. 

Common  observations  would  lead  us  to  expect  that  in  a 
low  state  of  the  fires,  when  the  large  lake  is  for  the  most 


160  VOLCANIC  ACTION 

part  thinly  crusted  over,  the  point  of  greatest  heat  and 
action  would  be  toward  the  centre ;  instead  of  this,  it 
is  usually  at  the  margin,  and  often  in  oven-like  places 
partly  under  the  cover  of  the  border  rocks.  The  only 
explanation  that  now  appears  is  that  already  given,  —  that 
along  the  border,  under  cover,  the  outside  cold,  or  that  of 
the  atmosphere,  is  much  less  felt  than  over ,  the  central 
portion. 

One  of  the  secoiidary  results  over  the  floor  of  the  crater  of 
the  projectile  work  is  the  making  of  the  fantastic  driblet- 
cones,  formed  often  about  blow-holes  out  of  the  descending 
clots  and  drops  and  Avorming  streamlets,  as  already  explained. 
Occasionally  the  particles  of  the  projected  lava  are  small  and 
descend  in  small  showers  of  loose,  smooth-faced,  but  variously 
shaped  bullets  and  granules  around  the  vent ;  and  this  is 
the  nearest  the  crater  at  present  comes  toward  producing 
cinder-cones. 

Besides  making  driblet-cones,  the  projectile  work  raises 
somewhat  the  borders  of  the  lakes.  Further,  the  small  over- 
flows, lapping  in  succession  over  the  borders,  often  make 
them  steep,  and  keep  increasing  their  height  until  a  heavier 
outflow  sweeps  one  side  or  another  away. 

A  third  incidental  result  of  the  projectile  action  is  the 
making  of  capillary  glass,  or  Fele's  hair,  from  the  glassy  part 
of  the  lavas.  In  the  jetting  and  splashing  of  the  lavas  the 
flying  clots  and  drops  pull  out  the  glass  into  hairs,  —  just  as 
takes  place  in  the  drawing  apart  of  a  glass  rod  when  it  is 
melted  at  middle.  Mr.  Brigham  says  that  "the  drops  of 
lava  thrown  up  draw  after  them  the  glass  thread,  or  some- 
times two  drops  spin  out  a  thread  a  yard  long  between 
them."  His  new  observations  of  1880^  accord  with  this 
explanation,  but  are  remarkable  for  the  length  and  size  of 
Pele's  tresses  reported  as  hanging  from  the  roofs  of  the 
fiery  recesses. 

1  American  Journal  of  Science,  1887,  xxxiv.  22. 


IN   THE   ORDINARY   WORK   OF    KILAUEA. 


161 


The  microscopic  structure  of  the  capillary  glass  has  been 
studied  with  care  by  C.  Fr.  W.  Krukenberg/  In  his  fifty 
fio-ures,  a  few  of  which  are  here  copied,  the  glassy  fibres  are 
sometimes  forked  or  branching,  sometimes  welded  at  cross- 
ings,  and   often   contain   air-vesicles  (o,  4j  and   microscopic 


Pelf's  Hair. 

crystals  (1,  2,  o),  often  tubidar  (1,  2)  through  the  draw- 
ing out  of  a  minute  air-vesicle.  They  also  show  that  the 
air-vesicles  sometimes  continued  expanding  as  the  glass  was 
drawn  out,  and  that  the  hair  is  often  enlarged  about  enclosed 
crystals.  The  crystals  are  rhombic,  as  in  the  figures.  The 
facts  make  it  evident  that  the  glass  is  far  from  being  pure 
glass. 


3.   The  Effects  of  the  Expansive  Force  of  Vapors  within  the 
Lavas.  —  Vesiculation  and  its  Mechanical  P>fects. 

Orifjln.  —  Vesiculation,  the  making  of  bubble-like  cavities 
in  a  melted  rock,  is  a  noiseless  unseen  effect  of  the  vapors 
that  are  rising  and  expanding  ivithin  the  lavas.  The  expan- 
sion necessary  to  produce  them  is  resisted  l\y  the  cohesion  in 
the  lava  and  l)y  the  pressure.  Consequently  it  is  a  very  com- 
mon feature  of  the  easily  fusible  volcanic  rock  basalt,  but  not 
of  trachyte  or  rhyolyte,  except  in  pumice,  the  glassy  scoria 
of  these  rocks  ;  and  even  this  glass  (obsidian)  commonly  holds 
to  its  moisture,  if  it  contains  anv,  without  vesiculating;. 

Owing  to  superincumbent  pressure,  the  maximum  depth 
of  vesicles  is  small,  as  has  long  been   recognized  ;   but  how 

^  Micrographie  der  Glasbasalte  voni  Hawaii  ;  petrographische  Untersuchung, 
38  pp.  8vo,  with  4  plates,  Tiibiiigen,  1877. 

21 


162  VOLCANIC  ACTION 

small  in  basalt  or  any  other  rock,  has  not  been  ascertained 
by  experiment.  It  probably  does  not  occur  in  the  Hawaiian 
Islands  below  a  depth  of  a  hundred  feet.  Above  the  lower 
limit  vesicles  may  increase  in  number  and  size  toward  the 
surface,  and  be  largest  in  the  scum  or  crust,  as  within 
Kilauea  ;  but  this  variation  upward   is  not  always  a  fact. 

Kinds.  —  Five  styles  of  vesiculation  may  be  distinguished 
in  the  Kilauea  ejections,  two  of  which  characterize  stony 
lavas,  and  three  scorias. 

1.  That  of  the  ordinary  lava-stream  of  the  floor  of  the 
pit.  The  vesicles  are  oblong  and  of  ii-regular  shape,  and  con- 
stitute from  less  than  one  to  fifty  or  sixty  per  cent  of  the 
mass  of  the  rock.  The  form  is  spherical  when  the  vesicles 
are  very  few  and  small. 

2.  That  of  the  common  stony  sj^herically  vesiculated  lava. 
The  vesicles  make  thirty  to  sixty  per  cent  of  the  mass,  and 
are  too  small  to  be  elongated  much  by  the  flow.  This  kind 
of  lava  occurs  in  streams  outside  of  Kilauea,  and  in  many 
about  the  slopes  of  Mount  Loa. 

The  best  example  of  it  I  have  seen,  and  the  basis  of  the 
following  description,  is  that  of  the  1880-1881  Mount  Loa 
flow,  near  Hilo.  The  small  uniformly  crowded  vesicles  con- 
stitute about  forty  per  cent  of  the  mass.  They  characterize 
the  lava,  with  scarcely  any  change  in  size  and  numbers,  to  a 
depth  (as  I  found  in  a  tunnel  within  the  lava-stream  whose 
floor  was  similar)  of  ten  or  twelve  feet.  Below  this  depth 
of  ten  or  twelve  feet  the  lava,  as  I  learned  from  Rev.  E.  P. 
Baker  of  Hilo,  is  probably  more  solid,  this  being  usually  the 
case. 

The  scoriaceous  kinds  are  — 

3.  That  of  the  glassy  scoriaceous  crust  of  the  lava-stream 
inside  of  Kilauea,  and  of  the  scum  of  its  lava-lakes  (p.  70). 
The  vesicles  are  sixty-five  to  seventy-five  per  cent  of  the 
mass  ;  they  are  elongated,  those  at  top  mostly  closed,  those 
of  the  bottom  of  the  crust  commonly  very  large.     The  half- 


IN   THE   ORDINARY    WORK   OP   KILAUEA.  163 

solid  crust  of  the  lake  is  sometimes  so  thin  that  stones 
thrown  on  it  slump  through.  The  glass  is  easily  fusible,  and 
hence  its  rapid  fusion  and  cooling.  An  analysis  of  this 
scoria-crust  by  Prof.  0.  D.  Allen  proved  it  to  have  the  com- 
position of  ordinary  basalt.^  No  analysis  has  been  made  of 
the  stony  lava  of  Kilauea  for  comparison. 

4.  Ordinary  scoria,  such  as  is  common  about  cinder-cones 
outside  of  the  crater,  mostly  stony  in  texture  ;  the  vesicles 
sixty-five  to  ninety-five  per  cent  of  the  mass. 

5.  Spongy  thread-lace  glassy  scoria,  occurring  as  a  layer 
twelve  to  sixteen  inches  thick  over  the  southwestern  border 
of  Kilauea,  as  stated  on  page  44 ;  the  vesicles  ninety-eight  to 
ninety-nine  per  cent  of  the  mass ;  their  walls  in  the  coarser 
varieties  sieve-like  or  reticulated,  in  the  finer  like  thread-lace 
in  texture.  Similar  spongy  scoria  is  reported  as  occurring 
at  the  summit  of  Mount  Loa  and  about  the  sources  of  some 
of  the  Mount  Loa  hiva-llows. 

Since  a  cubic  inch  of  the  finer  thread-lace  scoria  contains 
only  VI  per  cent  in  bulk  of  rock  material,  a  layer  of  solid 
basalt  glass  one  inch  thick  would  l^e  sufficient  to  make  a 
sixty-inch  layer  of  the  spongy  material,  and  probably  a 
seventy- five  to  a  hundred  inch  layer  of  the  much  more 
common  coarser  variety,  in  which  are  some  large  vesicles 
occasionally  half  a  cubic  inch  in  size. 

^  Professor  Allen's  analysis  (American  Journal  of  Science,  1879,  3d  series,  xviii. 
134)  is  in  column  A,  below.  For  comparison  the  composition  is  added  of  (B)  the 
doleryte  (diabase)  of  West  Rock,  New  Haven,  Conn.,  of  Triassic  age,  by  Mr.  G.  W. 
Hawes  (Ibid.,  1875,  ix.  186),  and  of  (C)  a  "  typical"  basalt  from  Buffalo  Peak,  east 
of  the  west  fork  of  the  Platte,  between  the  two  Parks,  by  R.  W.  Woodward  (De- 
scriptive Geolo,t,'y,  "  Geology  of  the  Fortieth  Parallel,"  1877,  ii.  126) 

SiOa  AUG;,  FeoOs  FeO  MnO  MgO  CaO  NaoO  K.O  ign.           P.,05 

A         50.75    16.54  2.10     7.88  trace  7.65    11.96   2.13  0.56  0.35           =  90.92 

B        51.80   14.21  3.55    8.26  0.42  7.63  10.68   2.15  0.39  0.63            0.14  =  90.86 

C        49.04   18.11  2.71     7.70  trncp.  4.72  7.11   4.22  2.11   1.29  TiO.2  2.46  =  99.47 

I  add  that  I  do  not  cite  here  the  analyses  of  the  rocks  and  volcanic  glass  of 
Kilauea  made  by  another  for  me  and  published  in  my  "  E.xpedition  Report,"  be- 
cause they  are  erroneous  and  should  be  rejected. 


164 


VOLCANIC   ACTION 


The  vesicles  of  the  finest  kind  are  mostly  one  thirtieth  to 
one  fortieth  of  an  inch  in  diameter,  like  those  of  the  1880- 


Cells  of  thk  Thrkad-lace  Scoria. 


1881  Mount  Loa  flow ;  but  their  walls  are  reduced  to  threads 
corresponding  to  the  edges  of  polygonal  vesicles.  Fig.  1 
shows  the  general  appearance  of  the  surface  in  a  maonified 


IN   THE   ORDINARY   WORK   OF   KILAUEA.  165 

view.  The  forms  of  the  skeleton  polygonal  cells  are  for  the 
most  part  either  twelve-sided  or  fourteen-sided  figures,  having 
a  perimeter  of  ten  or  twelve  pentagonal  faces  in  two  alter- 
nating rows,  and  bases  of  five  or  six  sides.  The  twelve-sided 
cells  are  bounded  by  the  edges  of  pentagonal  dodecahedrons 
such  as  come  from  the  mutual  pressure  of  spheres,  except 
that  they  are  distorted  usually  by  compression  and  by  elonga- 
tion or  abbreviation.  The  fourteen-sided,  which  are  much 
the  most  common,  are  similar  to  the  twelve-sided  in  general 
form,  but  have  hexagonal  bases.  Fig.  2  is  a  side  view  and 
Fit;-.  3  an  end  view  of  one  of  the  latter  kind,  and  Fig.  4  shows 
a  group  of  such  cells  as  seen  over  the  surface  of  the  scoria 
(a  cut  or  broken  surface,  for  it  is  impossible  to  handle  a 
piece  of  the  scoria  without  breaking  off  bits  of  the  brittle 
threads).  Fig.  6  is  another  of  the  fourteen-sided  kind  of  less 
symmetrical  form,  as  is  common.  One  of  the  pentagonal 
dodecahedrons  is  shown  in  Fig.  7,  and  another  in  Fig.  8. 

There  is  often  a  more  complex  system  of  network  through 
other  crossing  contour-threads,  but  the  simpler  forms  are 
referable  to  those  represented.  The  inside  of  the  base  of 
one  of  the  large  and  therefore  less  regular  forms  is  shown  in 
Fig.  5  ;  the  diameter  was  about  one  twentieth  of  an  inch.  In 
the  largest  vesicles  the  walls  are  openly  reticulated. 

The  threads  of  tliis  thread-lace  scoria  are  not  rounded,  but 
parts  of  the  conto\n\s  of  the  three  elliptical  cells  that  were 
there  in  contact ;  and  Fig.  0  shows 
a  portion  of  one.  Having  this 
form,  the  glassy  material  of  the 
threads  is  thickest,  and  therefore 
of  darkest  color,  at  the  centre  ; 
and  they  are  still  thicker  and 
darker  at  the  angles  or  jimctions 
of  three  threads.  This  glassy  scoria  calls  to  mind  the  vesic- 
ulation  of  an  obsidian  b}^  a  high  heat,  converting  it  into 
pumice  or  scoria  because  of  its  occluded  water,  as  illustrated 


166  VOLCANIC   ACTION 

by  Professor  Jucld,  and  also  by  Mr.  Iddings  in  experiments 
with  the  obsidian  of  the  Yellowstone  Park.  The  Kilauea 
glass  must  have  been  penetrated  molecularly  with  water  to 
have  produced  such  a  result.  Its  ejection  took  place  after 
the  violent  projection  of  great  stones.  —  and  apparently  not 
long  after,  as  it  o^^erlies  directly  the  layer  of  stones. 

The  minute  delicacy  and  brittleness  of  the  threads  in  this 
scoria  suggest  a  way  of  making  fine  dust  by  volcanic  action, 
which  is  much  more  reasonable  than  that  of  mutual  friction 
of  projected  fragments  of  scoria  of  the  ordinary  kind  ;  it  thus 
helps  in  the  understanding  of  the  lofty  dust-clouds  of  Kra- 
katoa  and  Tarawera. 

Amount  of  Moisture  required  for  Vesicidation,  its  Distribu- 
tion, and  its  Origin.  —  The  facts  derived  from  the  crowdedly 
vesiculated  lava  of  1880-1881,  reaching  from  its  source  down 
to  Hilo,  over  thirty  miles,  and  throughout  the  whole  range 
remarkable  for  uniformity  and  for  depth  in  the  stream,  be- 
sides giving  an  opportunity  to  study  the  origin  of  the  vesicu- 
lation  and  the  amount  of  moisture  it  requires,  presents  also 
evidence  as  to  the  origin  of  the  moisture  in  the  conduit  and 
its  condition. 

1.  According  to  the  report  of  Rev.  E.  P.  Baker,  the  vesicles 
change  little  toward  the  summit  except  in  becoming  coarser, 
with  thinner  walls,  at  the  source.  From  the  mean  size,  one 
thirty-fifth  of  an  inch  in  diameter,  we  ol^tain  for  the  size  of 
the  jMrficJe  of  moisture  required  at  the  ordinary  pressure  to  fill 
one  of  the  vesicles,  '000,000,007  of  a  cubic  inch.  What  the 
size  actually  was,  under  the  pressure  and  the  temperature 
that  existed  at  the  time  of  vesiculation,  cannot  be  deter- 
mined. But  this  much  we  learn,  that  the  moisture  was  dis- 
tributed throughout  the  lava  in  a  state  of  extreme  division, 
actually  or  essentially  that  of  molecular  diffusion. 

2.  The  space  in  the  vesicles  is  forty  per  cent  of  the  mass, 
as  determined  from  the  specific  gravity  of  the  rock-material. 


IN   THE   ORDINARY   WORK   OF   KILAUEA.  167 

2*98,  and  that  of  the  mass  with  the  surface  varnished  to  ex- 
clude the  water,  1-88.  Tlie  required  water  is  hence  '0003 
per  cent  of  the  mass,  or  by  weight  -OOOl  per  cent ;  showing 
that  the  cunount  of  loater  I'equired  for  the  vedcidation  is  exceed- 
ingh/  small. 

From  the  thread-lace  scoria  we  find,  since  only  I'T  per  cent 
of  the  mass  is  solid  glass,  that  the  amount  of  moisture  re- 
quired to  produce  the  vesiculation,  at  the  ordinary  pressure, 
would  be  3-12-5  per  cent  of  bulk,  and  1-1  per  cent  by  weight. 
The  amount  of  moisture  was  hence  not  unusual  for  a  rock, 
although  the  vesicles  occupied  98*3  per  cent  of  the  mass. 

3.  The  source  of  the  flow  of  1880,  1881,  according  to  Mr. 
Baker,  was  about  11,100  feet  above  the  sea-level.  This  is 
2,575  feet  below  the  summit  of  Mount  Loa,  or  aljout  1,600 
feet  below  the  bottom  of  the  summit  crater.  Before  the  out- 
break the  liquid  lavas  were  active  within  the  crater  ;  that  is, 
the  length  of  the  conduit  above  the  place  of  outbreak  was 
then  about  1,800  feet.  On  account  of  the  pressure  of  1,800 
feet  of  liquid  lava  no  vesiculation  could  have  taken  place  at 
this  depth  inside  of  the  conduit ;  but  at  the  discharge  the 
lavas  escaped  from  the  pressure,  and  the  vesiculation  by 
means  of  the  diffused  moisture  must  have  then  begun. 
Whether  the  vesiculation  for  the  whole  stream  took  place 
at  or  near  the  source  cannot  be  decided  without  more  knowl- 
edge of  the  flow  and  its  actual  sources  than  we  now  have. 

4.  The  facts  also  tend  to  sustain  the  conclusion,  before 
expressed,  that  the  ingress  of  the  subterranean  waters,  what- 
ever their  source,  took  place  by  molecular  absorption ;  for  it 
produced  an  essentially  equable  molecular  distribution. 

T7ie  Distribution  and  Functio?is  of  Moisture  after  reception 
into  the  Conduit.  —  1.  The  above  conclusions  from  the  ve- 
siculation have  prepared  the  way  for  additional  deductions 
as  to  the  distribution  and  movements  of  the  moisture  in  the 
conduit.     After  its  reception  it  is  exposed  to  a  heat  at  least 


168  VOLCANIC   ACTION 

1500°  F.  beyond  the  critical  point  of  water  (773"  F.),  and  re- 
tains the  temperature  of  fusion  to  tlie  surface.  If  the  expan- 
sive force  has  at  the  ingress  under  the  pressure  any  effective 
vakie,  the  accession  of  the  moisture  will  diminish  somewhat 
the  density  of  the  lava,  that  is,  increase  its  bulk  ;  and  this  in- 
crease will  be  greatest  along  the  central  region  of  the  conduit, 
because  this  is  the  region  of  greatest  heat.  If  dissociation 
takes  place  the  increase  is  still  greater,  as  it  adds  to  the 
bulk  of  the  moisture.  It  is  a  question,  therefore,  whether 
the  pressure  of  the  denser  lateral  lavas  of  the  conduit  would 
not  have  some  effect  toward  producing  an  upward  movement 
along  the  hotter  central  region. 

2.  The  mechanism  of  the  volcano,  as  regards  these  inside 
vapors,  seems  then  to  be  this  :  {a)  a  molecular  absorption,  at 
depths  below,  of  subterranean  waters  from  regions  either 
side  ;  {h)  a  rise  of  the  lavas,  thus  supplied  with  moisture, 
along  the  conduit  from  some  cause  (see  beyond  on  "•  the 
ascensive  force  of  the  conduit  lavas  "),  and  perhaps  partly  in 
consequence  of  the  vapors  present ;  (c)  after  reaching  a  level 
where  the  pressure  is  sufficiently  diminished,  a  union  of  the 
molecules  of  water  into  gas-particles,  p}'oduclii(i  by  their  ex- 
pansive force  vesiculatiou  ;  [d)  a  further  union  of  particles 
into  bubbles,  when  the  vapors  are  sufficiently  abundant,  in 
order  to  exert  the  greater  expansive  force  required  to  escape 
through  the  surface  of  the  lavas,  producing  jyrojectile  residts. 

Mechanical  Effects  of  Vesicidation.  —  Vesiculation  tends  in 
a  quiet  way  to  increase  bulk,  as  the  above-mentioned  facts 
illustrate.  It  therefore  will  give  increased  Jieight  to  the 
liquid  lava  in  a  conduit.  How  deep  down  this  effect  is  ap- 
preciable is  a  point  of  much  importance  in  its  bearing  on  the 
movements  and  levels  of  the  lavas  of  conduits.  If  only  to  a 
depth  of  two  hundred  feet,  an  average  of  twenty  per  cent  of 
vesicles  would  add  only  forty  feet  to  the  lieight  or  level  of 
the  surface. 

But  if  the  vapor  particles  at  all  deeper  depths  are,  through 


IN   THE   ORDINARY   WORK   OF   KILAUEA.  169 

iheir  expansive  force,  undergoing  gradual  expansion  as  they 
work  their  way  or  are  carried  upward,  we  are  still  further  in 
the  dark  as  to  the  amount  of  effect  of  vapors  on  the  bulk  of 
the  lavas  in  a  conduit.  After  the  author's  observations  of 
1840,  he  was  led  to  question,  as  is  stated  in  his  "'  Expedition 
Report,"  whether  the  effects  from  this  means  might  nut  be 
sufficient  to  account  for  much  of  the  excess  of  elongation  of 
the  Mount  Loa  column  over  that  of  Kilauea.  This  is  ob- 
viously not  so.  But  how  much  the  elongation  is,  is  an  impor- 
tant question,  and  it  has  still  to  remain  unanswered. 

4.  ayork  of  varors  (iexkkated  ultshje  of  the  condlit  :    fractures, 
Displacements,  and  other  Results. 

The  conduit  lias  hot  rocks  around  it ;  and  beneath  the 
floor  of  the  crater  there  are  hot  rocks  about  and  over  its 
upper  extremity.  The  descending  waters  are  driven  back  as 
vapor,  and  usually  in  a  harmless  manner.  But  a  sudden  in- 
cursion of  subterranean  waters  happening  under  any  circum- 
stances, might  produce  confined  vapors  of  great  amount  and 
force.  The  natural  effects  of  the  pressure  of  such  confined 
vapors  are  fractures,  elevations,  and  subsidences,  and,  where 
pressure  is  brought  to  bear  in  a  confined  place  on  a  source  of 
liquid  lavas,  their  injection  into  any  open  fissure  at  hand. 

These  effects  belong  mostly  to  times  of  eruption  ;  but  in  a 
lighter  form  they  may  be  part  of  the  ordinary  work  of  the 
crater.  The  lava-lakes  of  the  bottom,  even  in  quiet  times, 
often  have  large  overflows,  and  also  outflows  through  fissures, 
that  is,  both  superflnent  and  effluent  discharges  ;  and  it  is 
probable  that  the  cause  here  considered  may  be  the  occasion 
of  part  of  them. 

Confined  vapors  are  often  generated  also  by  the  action 
of  the  heat  of  a  lava-flow  on  moisture  underneath  it.  As 
rains  fall  almost  every  day  at  Kilauea,  there  must  be  more 
or  less  moisture,  underneath  many  parts  of  the  cold  floor  ;  and 
if  a  few  hours'  flow  from  the  great  lake  should  flood  it  with 

22 


170  VOLCANIC   ACTION 

liquid  rock,  its  2000°  F.,  which  the  bottom  of  the  stream 
carries  along  and  does  not  at  once  lose,  would  make  vapor 
out  of  the  moisture,  having  great  expansive  force.  The  large 
dome-shaped  bulgings  of  the  lava-streams  and  other  undula- 
tions of  the  surface  may  thus  be  accounted  for ;  and  many  of 
the  steaming  fractures  of  the  floor  as  well  as  those  of  the 
domes  may  have  the  same  orighi. 


B.     THE  ASCENSIVE   ACTION    IN   THE   LAVA-COLUMN. 

Evidence.  —  The  evidence  in  favor  of  an  uplifting  action 
by  the  ascensive  force  has  been  presented  on  pages  76,  109. 
It  is  briefly  as  follows  :  — 

1.  The  observations  in  1846  by  Mr.  Chester  Lyman  de- 
monstrate that  in  six  years  the  lower  pit  of  1840,  averaging 
ten  thousand  feet  by  twenty-five  hundred  in  its  diameters 
and  nearly  four  hundred  feet  in  depth,  had  gradually  become 
obliterated,  and  chiefly  through  an  uplift  of  the  floor ;  for 
the  floor  bore  on  its  surface  the  talus  of  lava-blocks  that  had 
fallen  from  the  walls.  Overflows  had  done  part  of  the  work, 
but  "  subterranean  force,"  as  Mr.  Lyman  concluded,  the  larger 
part.  Mr.  Coan,  who  was  with  Mr.  Lyman  at  the  time,  ap- 
preciated the  evidence,  and  later  described  the  lifting  as  "  not 
uniform  in  all  parts ;  as  sometimes  taking  place  here  and 
there  abruptly  ;  but  as  producing  nearly  uniform  results,  ex- 
cept a  greater  rise  toward  Halema'uma'u." 

2.  In  1868  Mr.  Brisrham  arave  further  evidence  as  to  the 

o  o 

Lyman  ridge  by  the  representation  of  what  remained  of  it  in 
1865  on  his  valuable  map,  though  not,  as  his  memoir  shows, 
understanding  its  origin.  Besides  this  the  painting  of  the 
crater  of  about  the  same  date  (1864  or  earlier)  by  Mr.  Perry 
(p.  87),  afforded  confirmatory  proof  as  to  its  position  and 
extent  at  that  time. 

3.  In  1848  Mr.  Coan  observed  that  a  cone  of  broken  lava, 
that  had  formed  within  the  Halema'uma'u  basin,  was  lifted 


IN    THE   ORDINARY   WORK   OF   KILAUEA.  171 

by  "  subterranean  action,"  as  he  argued,  because  only  slight 
additions  were  made  to  its  outside  by  ejections.  It  con- 
tinued to  rise  bodily  until  it  was  as  high  as  the  near 
walls  of  Kilauea.  Between  1880  and  1882  another  debris 
cone  began  in  the  basin  of  Haleraa'uma'u,  wliich,  as  he 
describes,  rose  in  like  manner  without  additions  to  its 
summit,  and  finally  became  two  hundred  feet  or  more 
high ;  this  cone  continued  to  exist  until  the  eruption  of 
1886. 

The  subterranean  force  appealed  to  was  plainly  force  aris- 
ing in  some  way  from  the  lavas  beneath.  Mr.  Coan,  in  his 
letters,  supposed  that  the  lifting  was  produced  by  the  injec- 
tion of  the  lavas  of  the  conduit  into  open  spaces  between  the 
solid  layers  below. 

4.  Again,  in  the  summer  of  1886,  three  months  after  the 
eruption  of  that  year,  the  debris  from  the  fallen  and  falling 
walls  of  Halema'uma'u  were  made  into  a  cone  occupying  a 
large  part  of  the  interior  of  the  basin  ;  and  from  August  on- 
ward, it  was  apparent  that  the  cone  so  made  was  slowly  rising, 
though  having  little  outside  additions;  in  October  of  1886, 
its  top  was  on  a  level  with  the  rim  of  the  basin ;  in  January, 
two  hundred  feet  higher,  so  as  nearly  to  overtop  the  south- 
eastern Kilauea  walls.  It  was  early  apparent  to  visitors  at 
the  crater  that  the  elevation  was  through  action  l)elow ;  and 
soon  the  conclusion  was  general,  among  observers,  that  the 
cone,  as  expressed  in  the  words  of  Mr.  Dodge,  of  Jan.  14, 
1887,  was  "  rising  slowly  as  though  floating  on  the  surface  of 
the  new  lava-lake."^ 

^  American  Journal  of  Science,  xxxiv.  70.  When  at  Honolulu,  Mr.  Parinelee, 
of  that  place,  informed  the  author  that  in  August  of  1886  he  made  observa- 
tions on  the  rate  of  change  of  level,  by  sighting  from  the  Volcano  House  veranda 
over  a  post  one  hundred  yards  in  front  of  the  house,  and  marking  the  cliange  of  the 
line  of  sight  on  a  pillar  of  the  veranda.  His  observations  were  made  between  the 
19th  and  21st  of  the  month.  On  the  first  day  the  rise,  according  to  his  calculated 
result,  was  sixteen  feet  ;  on  the  second,  seventeen  feet  ;  and  on  the  third,  eight 
feet.  These  numbers  are  large.  They  were  not  verified  by  observations  near  the 
cone.     They  at  least  prove  progress  in  the  elevation. 


172  VOLCANIC  ACTION 

The  ascensive  force  was  thus  proved  to  be  great,  and  its 
effects  to  have  fundamental  significance. 

Method  of  Action.  —  It  is  a  question  whether,  in  the  lift 
of  the  floor  of  the  great  crater  in  1823,  1832,  1840,  1868,  the 
lavas  of  tlie  lava-conduit  acted  by  direct  thrust,  or  through 
injections  into  s[)aces  between  the  layers  of  solidified  lava  be- 
neath it.^  The  facts  favor  strongly  the  former  of  these  views. 
In  the  first  place,  the  lateral  thrust  in  the  upper  lavas  of  a 
conduit  is  necessarily  feeble  ;  for  the  conduit  there,  or  near 
by,  opens  to  the  surface.  Then,  secondly,  it  is  quite  certain 
that  the  breadth  of  the  Kilauea  conduit  at  top  has  been,  at 
the  times  of  these  uplifts  of  the  floor,  large  enougli  to  i\ct 
somewhat  equably  against  the  floor.  Thirdly,  since  the  floor 
kept  its  even  surface  as  it  fell  at  the  great  eruption  of  1840, 
it  must  have  followed  down,  as  already  urged,  the  subsiding 
lavas.  The  flotation  method,  or  that  by  direct  thrust,  seems 
therefore  to  be  the  right  one.  It  is  the  obvious  explanation 
of  the  lifting  of  the  debris  cones  of  Halema'uraa'u. 

Kilauea  affords,  as  has  been  indicated,  facts  illustrating 
the  details  connected  with  the  lifting  movement. 

FauU-jolanes  of  the  vp-and-down  Movements  about  the 
Pit.  —  {1)  The  down-plunge  of  1823,  1832,  and  1840  left, 
for  the  most  part,  vertical  walls  bounding  the  '■  lower  pit  " 
so  made.  There  is  evidence  that  these  were  fault-walls;  that 
is,  planes  of  fracture  with  a  vertical  displacement  along 
them  equal  to  their  height,  or  about  four  hundred  feet  in 
1840  and  six  or  eight  hundred  feet  in  1823.  In  the  reverse 
movement — that  is,  the  rise  after  the  down-plunge  of  1840  — 
the  old  floor  was  carried  up  along  the  same  fault-planes. 
The  rate  of  rise,  as  shown  on  page  10,  was  seventy  to  one 
hundred  and  tliirty  feet  a  year,  which  is  to  be  divided  be- 
tween {a)  overflows,  (h)  vesiculation  if  this  had  any  effect, 
and  (c)  ascensive  force  apart  from  vesiculation. 

1  The  latter  is  the  explanation  adopted  by  Mr.  Brii,^hani  in  his  paper  of  July, 
1887,  American  Journal  of  Science,  xxxiv.  19. 


IN   THE   ORDINARY   WORK   OF   KILAUEA.  173 

Further  :  these  vertical  fault-planes  of  1840,  and  others 
subordinate  to  them  along  the  border  regions,  appear  to  have 
determined  the  chief  places  of  eruption  —  that  is,  of  lava-lakes, 
cones,  ovens,  and  opened  iissures  —  in  Kilauea  durinr/  the  7iext 
flurty  years.  They  were  plainly  the  occasion  of  the  wonder- 
ful girt  of  fires,  four  miles  long  and  half  a  mile  wide,  which 
was  three  times  repeated  after  the  year  1846  before  the  erup- 
tion of  1868  (in  1855,  1863,  and  1866),  while  the  interior 
plateau  suffered  relatively  little  change  from  erupting  forces, 
and  in  some  parts  was  growing  ohelo  bushes  and  ferns. 

The  position  of  the  ''canal"  in  Kilauea  in  1846,  described 
by  Mr.  Coan  and  also  Ijy  Mr.  Lyman  as  extending  around 
the  crater,  bounded  by  the  outline  of  the  old  black  ledge  and 
tlie  Lyman  ridge  of  lava-blocks,  and  which  became  gradually 
filled  by  inflowing  lavas  and  debris,  has  here  its  explanation. 
The  circumferential  fault-planes  of  the  pit  of  1840  coincided 
with  the  face  of  the  lower  wall  or  precipice.  The  debris 
which  fell  from  the  wall  necessarily  fell  to  the  floor  beyond 
the  plane,  and  there  began  the  making  of  the  talus.  Through 
the  fall  of  the  face  of  the  wall,  the  wall,  and  thereby  the  limit 
of  the  black  ledge,  retreated;  and  as  the  elevation  of  the  floor 
went  on,  an  interval  was  left  between  the  talus  and  the  limit 
of  the  black  ledge,  and  along  this  interval  lay  the  "  canal." 
The  annexed  figure  will  serve  to  illustrate  the  point,  notwith- 
standing tlie  assumptions  made 
in  it.  Let  h  h'  be  the  wall  of  the 
lower  pit,  four  hundred  feet  high, 
and  the  course  of  the  fault-plane  ; 
a  h,  the  floor  of  tlie  pit ;  h'  c,  the 
surface  of  the  black  ledge.  Let 
now  the  falls  from  the  wall  above 
e  make  the  talus  d  e  h  with  a  slope 

of  45°,  causing  therel^y  the  wall  (and  limit  of  the  black 
ledge)  to  retreat  to  g.  If  the  floor  be  now  lifted  four  hun- 
dred feet,  to   the  position  a'  h',  the  debris  of  the  talus  d  e  h 


174  VOLCANIC   ACTION 

would  make  an  elevation  at  top  equal  to  d'  e'  h,  besides 
filling  up  efh'(efh'=  cV  e'  V  =  I  d  e  h) ;  the  interval  Vf  g 
would  represent  the  canal,  and  d'  e'  h' ,  one  hundred  feet  high, 
the  ridge. 

If  the  floor  were  raised  fifty  feet  higher,  the  ridge  would 
be  lowered,  say  twenty-five  feet,  owing  to  material  that 
would  slip  down  into  the  canal ;  and  consequently,  the 
heierht  of  the  ridge  above  the  floor  over  the  centre  of  the 
crater  would  then  be  twenty-five  feet  less  than  before,  while 
twenty-five  feet  more  than  it  was  above  the  black  ledge.  If 
no  talus  had  been  formed  at  the  foot  of  the  wall,  an  uplift  of 
the  floor  of  five  hundred  feet  would  have  made  a  precipice  of 
one  hundred  feet  fronting  toward  the  black  ledge,  the  falls 
from  which  would  have  produced  a  steep  talus.  These  are 
two  conditions  in  the  different  parts  of  the  ridge  mentioned 
in  Mr.  Lyman's  paper. 

Faidt-planes  about  TIalemaumau. — In  Halema'uma'u, 
at  the  eruption  of  1876,  there  was  a  circumferential  fault- 
plane  ;  this  seems  to  be  implied  in  the  fact  that  the  return 
of  lava  was  mostly  through  vents  toward  the  walls,  little 
coming  up  at  the  centre,  and  the  fact  that  even  a  year  and 
a  half  afterward  the  action  was  greater  outside  of  the  cone 
than  at  its  centre.  At  the  discharge,  the  debris  from  the 
tumbling  walls  fell  beyond  the  fault-plane  and  made  an 
accumulation  of  blocks,  like  the  talus  of  the  lower  pit  of 
1840 ;  and  this,  as  Mr.  Dodge's  description  shows  and  the 
photographs  illustrate,  was  the  material  that  became  the 
cone  as  the   lifting  went  forward. 

Conclusion.  —  By  the  above  facts,  it  is  proved  that  the 
conduit  lavas  of  the  volcano  not  only  keep  up  the  supply  of 
heat,  and  carry  on,  by  means  of  the  vapors,  projectile  action 
and  vesiculation,  but  also  that  they  furnish  power  for  lifting, 
in  a  quiet,  unperceived  way,  the  floors  of  craters  with  what- 
ever  is  upon  them,  and   thus  raising   the  level  of  volcanic 


IN   THE   OKDINARY   WORK   OF   KILAUEA.  175 

activity ;  and  that  this  g-oes  forward  as  part  of  the  ordinary 
operations  of  the  crater.  The  action  has  long  been  recognized 
as  a  means  of  supplying  heat  and  lavas,  but  not  as  a  mechan- 
ical agent  to  the  extent  here  indicated.  The  force  at  vi^ork 
in  making  the  Gilbert  laccoliths  must  be  the  same ;  and  Mr. 
Gilbert,  in  his  report  on  the  Henry  Mountains,  gave  the  first 
intelligible  idea  of  its  power.' 

But  there  is  nothing  in  the  action  that  leads  us  to  suppose 
that  it  can,  under  any  probable  conditions,  make  jets  or  foun- 
tains of  lavas,  or  work  in  blow-hole  style.  Each  jet  over  a 
lake,  and  each  large  jet  in  a  lava-fountain,  has  its  local  pro- 
jectile cause  beneath  the  projected  column  of  lava,  and  can- 
not be  produced  by  any  general  upthrust  movement  in  the 
great  conduit.  The  imperceptibly  slow  uplift  and  fountain- 
making  are  incompatible  effects.  There  seems  to  be,  there- 
fore, no  foundation  for  the  comparison  of  the  lava-fountains 
to  the  projectile  effect  in  an  "  artesian  boring  made  to  a  stra- 
tum of  molten  rock  which  had  only  been  awaiting  an  oppor- 
tunity to  overflow."  ^ 

The  source  of  the  ascensive  7noveme7it  has  not  been  ascer- 
tained. It  is  most  commonly  referred  to  the  pressure  of 
the  earth's  crust  on  the  lava-reservoir  beneath,  arising  from 
subsidence  in  the  earth's  crust  from  secular  refrigeration. 
Another  explanation  appeals  to  vapors  from  the  deep  source 
of  the  lavas.  The  possibility  of  some  addition  to  the  force 
through  ascending  vapors  is  referred  to  on  page  168  of  this 
volume. 

C.    EFFECTS   OF   HEAT. 

From  Change  of  Temperature.  —  Contractional  effects  from 
cooling  —  that  is,  fractures  and  changes  of  level  —  should  be 
common  in  the  crater ;  for  each  stream  has  passed  from  a  tem- 

1  Mr.  W.  L.  Green,  Vestiges  of  the  Molten  Globe,  pp.  168,  272.  Mr.  Green's 
examples  are  taken  from  action  in  the  summit  crater ;  and  when  speaking  of  that 
crater,  this  point  will  be  again  considered. 


176  VOLCANIC   ACTION 

perature  of  2000°  F.  or  more  to  70°  or  80°  F.,  and  the  upper 
surface  of  a  stream  rapidly  so.  Besides  ordinary  shallow  frac- 
tures, the  cause  produces  also  an  imperfectly  columnar  struc- 
ture in  the  cooled  lava-stream  below  the  upper  foot  or  two. 
The  cracks  in  the  floor  of  Kilauea  often  expose  quite  good 
basaltic  columns  even  when  the  whole  thickness  of  the  layer 
is  hardly  a  dozen  feet. 

There  should  be  also  larger  effects  in  the  Kilauea  region 
arising  from  change  of  temperature  between  periods  of  great 
and  little  activity,  or  from  periodical  variations  in  the  heat 
below,  and  changes  of  level  in  the  lava  of  the  conduit.  But 
we  have  no  special  facts  to  report  in  illustration,  although 
there  are  cracks  innumerable  in  view  that  probaljly  have  this 
source. 

Tlie  Dissolving  Action  of  the  Liquid  Lavas.  —  (1)  The  refu- 
sion of  the  crust  over  the  surface  of  a  lava-lake  by  the  liquid 
lavas  is  —  as  the  history  has  shown  —  one  of  the  common 
occurrences  in  Halema'uma'u  and  other  lava-lakes.  The 
intervals  of  cooling  and  refusion  vary  in  length  from  a  few 
seconds  to  an  hour  and  longer.  The  crust  of  a  lava-lake  is 
often  only  the  thin,  easily  fusible  glassy  scum ;  but  thicker 
crusts  also  yield  to  the  heat. 

In  the  case  of  rapid  transitions,  the  cooling  may  be  due  to 
the  loss  of  heat  by  the  expansion  in  the  process  of  vesicula- 
tion  ;  and  if  the  vesiculation  takes  place  intermittently  for 
any  reason  (as  from  oscillating  movement  in  the  lava-column 
or  other  condition)  it  would  occasion  the  alternations  be- 
tween the  fused  and  crusted  state.  But  for  the  crustings  at 
longer  intervals  deeper  movements  may  be  concerned,  and 
more  study  is  needed  before  they  are  fully  understood. 

(2)  The  disa2)peara7ice  of  floating  islands  is  another  effect 
of  heat  and  chiefly  of  refusion  ;  for  in  some  cases  the  islands 
have  after  a  while  —  a  year  or  more  —  disappeared. 

(3)  The  destruction  of  dehris-cones  in  Halema'uma'u  is 
dependent  on   undermining  by  the   active  lavas  and  vapors 


IN    THE   ORDINARY   WORK   OF    KILAUEA.  177 

beneath ;  and  in  one  case  the  destruction  was  probably  com- 
pleted before  a  period  of  eruption. 

The  debris-cone,  fifteen  hundred  to  two  thousand  feet 
broad  at  base,  which  now  occupies  the  centre  of  the  Hale- 
ma'uma'u  basin,  is  already  in  process  of  dissolution,  as 
stated  on  page  110.  It  made  no  increase  in  height  during 
the  summer  of  1887,  but,  instead,  rather  lost  ground  through 
the  changes  going  on  ;  and  the  report  of  the  spring  of  1889 
tells  of  a  loss  already  of  eighty  feet  in  its  height,  —  not 
eighty  feet  of  its  summit,  but  of  the  lower  part  that  was 
within  reach  of  or  in  contact  with  the  liquid  lavas. 

The  description  on  page  105  by  Professor  Van  Slyke  of  the 
cone  as  seen  by  him  in  July,  1886,  gives  particulars  as  to  the 
steam-holes  in  and  beneath  the  cone,  and  of  the  blowing-cone 
work  which  began  this  work  of  destruction. 

This  destructive  work  brings  the  cone  to  its  end  either  be- 
fore or  during  a  period  of  eruption  ;  and  a  floating  island 
may  be  the  last  phase  before  its  disappearance. 

Oldening  of  New  Lava-lakes.  —  With  the  intensifying  of 
the  fires  of  the  crater  there  has  often  been,  as  the  history 
shows,  an  opening  of  lakes  over  the  interior  of  the  crater, 
and  especially  along  the  borders  of  Kilauea,  or  the  region  of 
the  black  ledge.  Such  facts  signify,  as  has  been  explained, 
that  the  broad  underlying  conduit  of  Kilauea,  which  is  like 
a  great  reservoir  of  lavas  beneath  the  pit,  reaches  at  such  a 
time  up  to  the  surface,  not  only  in  the  Halema'uma'u  basin 
through  the  great  conduit,  but  also  in  minor  lakes  through 
secondary  conduits.  It  is  a  query  whether  this  has  ever  been 
brought  about  by  new  sources  of  vapor  starting  in  the  under- 
lying reservoir  as  a  consequence  of  subterranean  conditions  ; 
whether  hot  vapors  from  such  a  source  have  not  forced  a  way 
through  to  the  surface  in  consequence  of  their  own  dissolving 
and  fusing  heat  and  that  of  the  lavas,  and  thus  have  made 
a  new  lake,  —  as  ascending  air  from  the  l)ottom  of  an  ice- 
covered  pond  makes  a  hole  through  the  covering  of  ice.     But 

23 


178  VOLCANIC   ACTION 

such  lakes,  as  remarked  on  a  preceding  page,  are  generally 
begun  over  fissures  ;  and  it  may  be  that  fissures  under  the 
general  increased  activity  are  all  that  are  needed  for  the 
result. 

Extending  the  Limits  of  the  Conduit  hy  Fusion.  —  Another 
suggestion  comes  from  the  fusing  power  of  the  Halema'uma'u 
lavas.  If  these  lavas  can  slowly,  even  at  their  surface,  fuse 
stony  lavas,  what  is  the  extent  of  the  fusing  power  at  depths 
below  where  there  is  greater  heat  ?  An  increase  in  the  heat 
from  a  subterranean  cause  would  necessarily  widen  the  limits 
of  the  conduit.  It  is  a  question  wliether  an  extended  sub- 
terranean bed  of  liquid  lava,  thick  enough  to  remain  per- 
manently liquid  in  spite  of  cooling  agencies  about  it,  can 
occupy  its  place  without  fusing  and  incorporating  with  itself 
any  solid  lavas  directly  underneath  it,  if  such  there  be.  A 
great  lava-conduit,  therefore,  has  probably  its  varying  phases, 
like  the  fires  at  the  surface,  and  includes  extremes  in  breadth 
or  enlargement  as  well  as  in  contraction.  The  widest  part 
should  not  be  at  the  summit  unless  the  cooling  agencies  are 
less  effective,  or  the  heat-making  causes  more  effective,  there 
than  elsewhere. 

The  Metamorphic  Action  of  the  Heed.  —  Metamorphic  ac- 
tion also  may  be  part  of  the  quiet  work  of  the  volcano.  The 
lava-column  has  its  enclosing  rocks,  and  at  temperatures 
varying  from  that  just  below  fusion  to  that  of  the  outside 
rocks ;  and  vapors  must  be  active  in  the  hot  regions.  The 
throat  of  tlie  conduit  may  well  be,  therefore,  a  region  of 
recrystallizations,  of  the  making  of  geodes,  or  the  lining  of 
fissures  with  crystals,  out  of  whatever  material  was  at  hand, 
and  different  kinds,  somewhat  according  to  the  tempera- 
ture. The  effects  of  such  metamorphism  are  exhibited,  be- 
yond question,  in  the  various  mineral  crystallizations  of  the 
ejected  masses  of  Vesuvius.  They  are  found  also  at  Kilauea, 
as  mentioned  beyond.  The  repeated  coolings  and  heatings 
(passing  often  to  fusings),  which  Kilauea  lava-lakes  so  well 


IN   THE   ORDINARY   WORK   OF   KILAUEA.  179 

illustrate,  suggest  an  explanation  also  for  the  feathery  angite 
detected  by  Prof.  E.  S.  Dana  in  the  lavas  of  Kilauea  as  well 
as  of  Mount  Loa,  as  described  beyond. 

D.    HYDROSTATIC    AND   OTHER   GRAVITATIONAL   PRESSURE. 

1.  The  hydrostatic  pressure  of  the  column  of  liquid  basalt 
is  2-8  to  2-9  times  that  of  water,  supposhig  the  lavas  while 
in  fusion  to  be  mainly  in  the  glassy  condition.  This  pressure 
was  early  recognized  by  Lyell  as  one  of  the  possible  causes  of 
rupture  in  volcanoes.  The  cause  may  have  its  effects  in  a 
quiet  way  over  the  bottom  of  Kilauea,  since  the  lavas  often 
stand  in  the  lakes  at  a  height  of  fifty  to  a  hundred  feet  above 
the  floor  outside  of  the  surrounding  cone ;  but  no  facts  yet 
observed  can  be  positively  referred  to  it. 

2.  Again,  there  may  be  undermimngs  and  therefore  sub- 
sidences in  the  ordinary  course  of  Kilauea  changes,  through 
discharsres  followino;  small  fractures.  Such  effects  over  the 
floor  of  the  pit  are  not  at  present  distinguishable  from  those 
of  other  modes  of  origin.  But  the  sinking  of  the  floor  of 
Halema'uma'u  in  the  spring  of  1889,  mentioned  on  page  123, 
is  probably  an  example  within  this  subordinate  pit. 

Having  thus  reviewed  the  ordinary  operations  of  the  crater 
—  that  is,  those  carried  forward  between  times  of  eruptions  — 
in  the  way  of  preparation  for  an  eruption,  the  next  inquiry 
is,  What  is  needed  to  produce  a  great  eruption  of  Kilauea  ? 
The  power  of  the  rising  vapors  and  that  of  the  ascensive 
conduit-lavas  —  the  two  chief  sources  of  ordinary  activity  — 
appear  to  be  too  feeble  for  any  such  result.  Can  eruptions 
take  place  without  any  increase  of  their  activity  within  the 
crater  beyond  what  has  been  described  ?     If  so,  how  ? 

Before  discussing  this  subject  the  history  of  the  summit 
crater,  Mokuaweoweo,  should  be  first  reviewed,  as  its  facts 
afford  important  illustrations  of  the  eruptive  methods. 


180  VOLCANIC  PHENOMENA 

B.    MOUNT   LOA,   AND   ITS   SUMMIT   CRATER, 
MOKUAWEOWEO. 

The  map  of  the  island  of  Hawaii,  reduced  from  the  Gov- 
ernment map,  making  the  frontispiece,  should  here  be 
studied.  It  will  enable  the  reader  to  appreciate  the  broad, 
almost  plateau-like  summit  of  the  mountain,  the  relative 
position  and  heights  of  Kilauea  and  the  Mount  Loa  crater, 
besides  other  points  of  interest  in  the  history  and  discussion 
beyond. 

The  present  form  of  the  summit  crater,  Mokuaweoweo,  is 
shown  on  the  map  (Plate  X.)  by  J.  M.  Alexander,  reduced 
from  the  results  of  his  survey.  The  height  of  the  highest 
point  given  on  it — 13,675  feet  —  differs  eighty-five  feet 
from  Wilkes's  determination  of  the  same  point  in  1841. 

The  history  of  the  summit  crater  is  mostly  a  history  of  the 
results  of  its  eruptions,  for  few  facts  have  been  observed 
respecting  the  action  within  the  crater.  It  has  excited  atten- 
tion when  an  eruption  has  been  in  progress  ;  but  the  chief 
outflows  have  begun  below  the  summit,  and  the  source  of  the 
outflow  is  usually  the  only  place  reached.  Still  there  is 
much  to  be  gathered  from  the  reported  facts.  The  records 
begin  with  the  year   1832. 

1.  Eruptions  of  Mount  Loa  from  1832  to  1868. 

1832,  June  20.  —  On  the  20tli  of  June,  1832,  according  to 
Rev.  Joseph  Goodrich,  lavas  were  discharged  from  several 
vents  about  the  summit.^  The  fires  continued  to  be  visible 
for  two  or  three  weeks,  and  were  seen  from  Lahaina,  on  the 
western  coast  of  Maui,  a  hundred  miles  to  the  northwest. 

1  Goodrich,  American  Journal  of  Science,  1834,  xxy.  201,  letter  of  Nov.  17, 
1832. 


Plate  X. 


7^ 


J^ejirrT/i  ,    3:aa  rnitca, 

t^r'CQ.     ,      3:e    Sr/. miles. 
Circiirtifer'ancc,  Oj 


PcT  I  <3%i  1  Tixti,  l?e  ale 
CDm.-VVilkee. 


r.S.TJocIgc 

'"^    /N20°E 


MAP   OF 

MOKUAWEOWEO, 

MAUNA    LOA, 

HAWAII. 

2,000  ft.  - 1  inch. 

Surveyed  by  J.  M.  Alexander. 
1885. 


IN   THE  HISTORY   OF   MOUNT  LOA.  183 

Nothing  is  known  of  any  large  discharge  of    lava,  and  no 
mention  is  made  of  accompanying  earthquakes. 

The  outbreak  of  Kilauea  in  1832  occurred  about  the  same 
time,  but  possibly  a  few  months  later. 

1834,  January  29.  —  Mr.  David  Douglas,  the  naturalist, 
who  was  the  lirst  to  ascend  Mount  Loa  and  determine  baro- 
metrically its  altitude,  describes  the  crater,  in  his  "  Journal,"  ^ 
as  having  great  chasms  in  the  bottom  that  he  could  not 
fathom  ''  with  a  good  glass  and  the  air  clear  of  smoke,"  and 
says  further  that  "  the  depth  to  the  bottom  on  the  east  side 
was  by  an  accurate  measurement  with  a  line  and  plummet 
1,270  feet;"  that  the  southern  part  of  the  crater,  "  where 
the  outlet  of  the  lava  had  evidently  been,  must  have  enjoyed 
a  long  period  of  repose."  He  mentions  hearing  light,  hissing 
sounds  from  fissures  in  the  summit,  that  might  "  perhaps  be 
owing  to  some  great  internal  fire  escaping."  He  adds: 
''  There  is  little  to  arrest  the  eye  of  the  naturalist  over  the 
great  portion  of  this  huge  dome,  which  is  a  gigantic  mass  of 
slag,  scorise,  and  ashes." 

1841,  January.  —  Captain  Wilkes  was  at  the  summit  dur- 
ing the  latter  part  of  January,  1841.^  Lieutenant  Eld,  by 
taking  angles  from  the  bottom  of  the  crater,  made  the  west- 
ern wall  784  feet  high,  and  the  eastern  470  feet.  The  only 
sign  of  activity  was  the  escape  of  steam  and  sulphur  gases 
from  many  deep  fissures  over  the  bottom,  especially  on  the 
west  side.  The  fissures  had  generally  a  N.N.E.-S.S.W.  direc- 
tion.    There  was   one  cinder  or  scoria  cone  at  the  bottom, 

1  Companion  of  the  Botanical  Magazine,  1836,  ii.  175,  and  in  a  letter  to  Captain 
Sabine,  dated  May  3,  1834  (Journal  of  the  Geographical  Society,  1834,  iv.  333). 
See  page  58,  on  the  letter  to  Dr.  Hooker  and  the  evidence  against  it. 

2  Narrative  of  the  Expedition,  iv.  152,  156,  159.  The  descriptions  of  the  crater 
are  from  descents  made  into  it  by  Dr.  G.  P.  Jndd  of  Honolulu  (p.  152)  and 
Lieut.  Henry  Eld  (p.  156).  Wilkes's  map  has  its  longer  diameter,  through  some 
mistake,  north  and  south  in  direction  ;  this  is  corrected  in  the  copy  on  the 
following  page. 


184 


VOLCANIC   PHENOMENA 


according  to  Dr.  G.  P.  Judd,  toward  the  southwest  side,  hav- 
ing a  height  of  about  two  hundred  feet.  Other  steam-cracks 
were  observed  outside  about  the  pit-crater  of  the  south-south- 
west end  ;  and  one,  which  they  "designated  the  great  steam- 
crack,  led  from  the  top  a  long  distance  down  the  sides  of  the 
mountain  toward  the  south ;  "  and  a  great  depth  was  indicated 


^'%.- 

/__:_.- 

■2' 

,^^S. 

w 

»r  PfuduiuTH  Peak 

.m 
IM 

12^4          SOOOtt: 

The  Summit  Crater. 

by  the  reverberations  from  a  block  of  lava  which  was  dropped 
into  it.  Small  driblets  of  lava  were  observed  along  some  of 
these  fissures,  indicating  feeble  ejections.  In  Wilkes's  map, 
as  shown  in  the  above  outline  copy,  seven  small  cones  are 
faintly  represented  on  the  bottom  of  the  crater,  although 
the  descriptions  speak  of  only  one. 


IN   THE   HISTORY   OF   MOUNT   LOA.  185 

1843,  Geeat  Eruption  commencing  in  January.  —  In 
January^  1843,  began  an  outflow  that  continued  for  about  six 
weeks.  Clouds  above  on  the  9th  made  the  first  announcement 
to  the  people  of  the  islands.  During  the  following  night,  ac- 
cording to  Dr.  L.  Andrews,^  a  brilliant  light  appeared  at  the 
summit,  looking,  as  Mr.  Coan  states,  like  "  a  small  beacon- 
fire."  ^  In  a  week  the  light  disappeared.  In  the  mean  time 
the  lavas  had  commenced  their  discharge.  Mr.  Coan  as- 
cended to  the  source,  about  eleven  thousand  feet  up,  and 
found  two  large  craters  near  together,  very  deep  and  active. 
The  stream  of  lava  flowed  toward  Mount  Kea,  but  gave  oft" 
a  westward  branch,  toward  Hualalai,  near  its  source.  At 
the  base  of  Mount  Kea  a  branch  went  northward  toward 
Waimea,  and  another  eastward  toward  Hilo.  Mr.  Coan  states 
that  over  the  crusted  surface  of  the  stream  were  many  steam- 
ing openings,  twenty  to  fifty  feet  broad,  down  which  he  saw 
the  lavas  rushing  along  the  tunnel-like  way,  "  with  awful 
speed,  some  fifty  feet  below  us ;  "  large  stones  thrown  on  the 
surface  were  carried  "  instantly  out  of  sight  before  sinking 
into  the  stream."  The  action  was  much  diminished  in  six 
weeks,  but  was  "  still  somewhat  vehement  at  one  or  two 
points."  In  March  of  1843  Messrs.  Paris  and  Coan  found 
snow  on  the  summit. 

Mr.  Andrews  states  that  during  the  progress  of  the  erup- 
tion Mr.  Wilcox  visited  Kilauea  and  found  no  signs  of 
sympathy. 

1849,  May. — A  brief  notice  of  brilliant  fires  at  the  sum- 
mit crater  in  the  month  of  May,  1849,  is  contained  in  a  letter 
of  Mr.  Coan's,  dated  January,  1851.  He  says  that  the  light 
was  first  noticed  after  the  extraordinary  activity  in  Kilauea. 
"I  cannot  say  that  they  were  coincident."     For  two  or  three 

1  Andrews,  Missionary  Herald,  xxxix.  .381,  letter  of  Feb.  6,  1843. 

2  Coan,  Ibid.,  xxxix.  463,  letter  of  Feb.  20,  1843  ;  xl.  44,  letter  of  April  5  ; 
American  Journal  of  Science,  1859,  2d  series,  xxvii.  411;  Life  iu  Hawaii,  1882, 
p.  270. 

24. 


186  VOLCANIC   PHENOMENA 

weeks  a  brilliant  and  lofty  column  of  light  was  seen  over  the 
mountain.  There  is  no  reported  evidence  as  to  any  surface 
outflow  of  lavas,  and  none  of  an  earthquake.^ 

1851,  August  8.  — A  short  flow  commenced  at  this  date  a 
few  miles  west  of  the  summit.^  From  Hilo  a  column  of 
clouds  was  seen  by  day,  which  was  fiery  by  reflection  at 
night.  The  eruption  continued,  so  far  as  could  be  seen  from 
Hilo,  only  three  or  four  days.     No  earthquake  was  reported. 

Mr.  William  T.  Brigham  in  1864  visited  the  flow,  and 
states^  that  the  outbreak  of  1851  occurred  about  a  thousand 
feet  below  the  summit,  ''or  two  hundred  feet  below  the  bot- 
tom of  the  crater."  He  estimated  the  length  of  the  stream 
at  "  ten  miles  and  the  average  breadth  less  than  a  mile,"  and 
the  volume  "  one  hundred  and  sixty  million  cubic  yards  of 
lava."  "  The  greater  part  is  the  pahoehoe,  although  some 
aa  occurs."  The  course  was  westward,  near  that  of  an  old 
stream  toward  Kealakekua. 

1852,  Great  Eruption  commencing  February  17.  —  The 
eruption  of  1852  began  only  six  months  after  the  brief  action 
of  1851,  as  if  its  supplement.  The  place  of  outbreak,  accord- 
ing to  Mr.  Coan,*  was  on  the  north  side  of  the  summit,  near 
that  of  1843.  When  first  seen  the  light  looked  like  "  a 
planet  just  setting"  over  the  top  of  the  mountain.  In  a  few 
minutes  the  whole  summit  was  brilliant,  and  Hilo  also ;  and 
a  stream  of  lava  commenced  its  flow  down  the  mountain. 
Forty  hours  later  the  fires  had  apparently  become  extinct. 

But  after  three  days,  on  the  20th,  the  chief  flow  began  at 

1  Coan,  American  Journal  of  Science,  1851,  2d  series,  xii.  82,  letter  of  January, 
1851. 

2  Ibid.,  1852,  xiii.  395,  letter  oC  Oct.  1,  1851;  and  D.  D.  Baldwin,  Ibid.,  p.  299, 
from  "  Polynesian  "  of  August  23,  1851. 

3  Volcanoes  of  the  Hawaiian  Islands,  1868,  4to,  p.  389. 

4  Coan,  American  Journal  of  Science,  1852,  xiv.  105,  219;  Life  in  Hawaii, 
p.  279. 


IN   THE   HISTORY   OF   MOUNT   LOA.  1S7 

a  point  on  the  eastern  side  about  ten  thousand  feet  above 
the  sea-level,  near  the  terminus  of  a  line  of  fissures  leadino: 
down  from  the  place  of  the  first  outbreak.  The  escajylng 
lavas  rose  at  first  in  a  lofty  fountain,  and  then  flowed  east- 
ward for  twenty  miles.  On  the  2Tth  Mr.  Coan  reached  the 
place  of  the  fountain,  approaching  it  on  the  windward  side 
within  two  hundred  feet.  He  found  the  lavas  playing,  as  he 
states,  to  a  height  of  four  to  five  and  seven  hundred  feet,  by 
angular  measurement,  in  ever-varyhig  forms  of  towers,  pyra- 
mids, and  spires,  and  with  variations  also  in  colors  from 
white  heat  at  base  to  red  above,  and  then  to  grayish  red 
and  gray. 

Great  volumes  of  lava  were  ascending  and  descending,  not 
intermittently  but  continuously  ;  and  the  "  surging,  roaring, 
booming  "  sounds  were  almost  deafening,  but  without  earth- 
quake from  beginning  to  end.  Ashes  and  capillary  glass  fell 
in  the  streets  of  Hilo.  The  stream  stopped  about  ten  miles 
from  the  village.  The  grand  eruption  was  in  blast  only 
twenty  days.     All  this  time  Kilauea  was  quiet. 

In  Jul}^  Mr.  Coan  ascended  again  to  the  crater  or  place  of 
discharge,^  and  found  the  fires  extinct.  He  says  a  kind  of 
"  pumice  "  was  abundant  and  widely  scattered  ;  "  we  found 
it  ten  miles  from  the  crater,  and  it  grew  more  and  more 
abundant  till  we  reached  the  cone,  where  it  covered  the 
whole  region  to  a  depth  of  five  or  ten  feet." 

An  ascent  to  the  active  fires  was  made  early  in  March  by 
Mr.  H.  Kinney^  and  Mr.  Fuller.  Mr.  Kinney,  speaking  of 
the  sounds  from  the  cataract  of  liquid  lavas,  says :  "  Its 
deep  unearthly  roar,  which  we  began  to  hear  early  on  the 
day  before,  waxed  louder  and  louder  as  we  drew  nearer  the 
action,  until  it  resembled  the  roar  of  the  ocean's  billows  when 
driven  by  the  force  of  a  hurricane  against  a  rock-bound  coast, 

^  Coan,  American  Journal  of  Science,  1853,  xv.  6.3. 

2  H.  Kinney,  American  Journal  of  Science,  1852,  xiv.  257,  from  the  "Pacific" 
of  San  Francisco  of  June  19,  the  letter  dated  Waiohinu,  Hawaii,  April  19,  1852. 


188  VOLCANIC  PHENOMENA 

or  like  the  deafening  roar  of  Niagara."  This  description  at- 
tests to  the  fountain-like  character  of  the  discharge ;  for  such 
sounds  do  not  come  from  flowing  lavas  unattended  by  earth- 
quake phenomena.  Mr.  Kinney  made  the  height  of  the  jets 
four  to  eight  hundred  feet.  He  reports  also  that  the  heat 
created  terrific  whirlwinds  which  stalked  about  like  so  many 
sentinels,  bidding  defiance  to  the  daring  visitor. 

Mr.  Fuller  states^  that  from  careful  calculations,  made 
*'  after  deliberate  discussion  with  Mr.  Kinney,"  "  some  of 
which,"  he  says,  "  have  been  confirmed  by  a  somewhat  ac- 
curate measurement  by  Mr.  Lyman  of  Hilo,"  the  diameter  of 
the  crater  from  which  the  fountain  rose  was  about  a  thou- 
sand feet ;  height  of  the  crater,  a  hundred  to  a  hundred  and 
fifty  feet ;  height  of  the  fountain,  two  to  seven  hundred  feet, 
and  rarely  below  three  hundred  feet ;  diameter  of  the  foun- 
tain, one  to  three  hundred  feet,  "  and  rarely  perhaps  reaching 
four  hundred  feet."  The  jet  of  fire  sometimes  shot  up  into 
a  tapering  gothic  spire  of  seven  hundred  feet,  then  rose  in  a 
grand  mass  three  hundred  feet  in  diameter,  but  varied  at  top 
with  points  and  jets  like  the  ornaments  of  gothic  architecture. 
He  adds  that  to  appreciate  the  most  terrific  element  in  the 
sublime  composition  you  should  stand  at  the  foot  of  a 
Niagara,  or  on  a  tempest-lashed  shore ;  for  "  the  force  neces- 
sary to  raise  two  hundred  thousand  to  five  himdred  thousand 
tons  of  lava  at  once  into  the  air  would  not  be  silent  in  its 
operations."  The  lava-stream  is  stated  to  have  a  depth,  in 
some  places,  of  two  or  three  hundred  feet. 

Mr.  E.  P.  Baker  states  that  on  the  route  from  Ainapo  to 
the  source  of  the  outflow  of  1852,  the  lavas  of  the  1852 
stream,  where  they  were  first  reached,  were  of  the  aa  kind  ; 
but  after  a  while  there  was  a  change  to  pahoehoe,  and  soon 
after  this  the  source  was  reached,  —  a  red  cone  in  the  midst 
of  an   extensive   bed   of  pumice.     Long  ditches  or  trenches 

1  Fuller,  American  Journal  of  Science,  1852,  xiv.  258,  letter  dated  Waiohinu, 
March  28. 


IN   THE   HISTORY   OF    MOUNT    LOA.  189 

occur  in  the  surface  of  the  region,  wliich  were  evidently  the 
beds  of  lava-streams,  their  sides  having  been  the  banks.  The 
flow  appears  to  have  had  a  single  outlet.  Water  boiled  at 
the  source  at  200°  F.^ 

1855,  Great  Eruption  commencing  August  11.  —  Dur- 
ing the  evening  of  August  11  a  glowing  point  of  light  was 
seen  at  a  height  of  twelve  thousand  feet  on  the  northeast 
slope  of  the  mountain.^  The  light  rapidly  extended,  and  it 
soon  became  evident  that  a  lava-stream  was  on  its  way  down 
the  mountain.     No  earthquake  had  announced  the  eruption. 

Mr.  Coan  ascertained,  through  his  excursions,  that  a  line 
of  fissures  extended  from  near  the  summit  for  "  five  miles  " 
down  the  northeast  side  to  the  place  of  outbreak,  along  which 
there  were  cones  of  volcanic  scoria  and  sand,  a  hundred  feet 
or  so  liigh,  that  had  been  thrown  up  at  the  points  of  greatest 
activity.  Descending  the  mountain  the  cones  became  lower 
and  less  frequent,  and  were  the  ragged  jaws  of  orifices 
throuQ:h  which  the  stream  of  lava  was  visible. 

The  place  of  outflow  was  a  crater  formed  over  a  fissure 
two  to  thirty  yards  wide.  The  lava  flowed  in  a  continuous 
stream  down  slopes  of  all  angles  from  less  than  one  degree  to 
verticality.  The  course  was  eastward  like  that  of  1852,  and 
it  finally  stopped  within  five  miles  of  Hilo. 

Mr.  Coan  describes  the  tunnels  in  the  lava-stream,  and 
speaks  of  the  lavas  seen  through  openings  as  moving  with 
great  velocity,  — "  estimated  to  be  forty  miles  an  hour." 
Some  of  the  steaming  openings  were  thirty  to  two  hundred 
feet  long,  and  the  flowing  lavas  were  fifty  to  a  hundred  feet 
below.  But  the  progress  of  the  front  of  the  stream,  where 
were    obstructions    of    trees,  jungles,    depressions,   etc.,  was 

1  Baker,  American  Journal  of  Science,  1889,  xxxvii.  53. 

2  Coan,  American  Journal  of  Science,  1856,  2cl  series,  xxi.  139,  144,  letters  of 
Sept.  27  and  Oct.  15,  1855;  Ibid.,  p.  237,  letter  of  Nov.  15,  1855;  Ibid.,  xxii.  240, 
letter  of  March  7,  1856  ;  Ibid.,  1857,  xxiii.  435,  letter  of  Oct.  22,  1856  ;  Life  in 
Hawaii,  p.  289. 


190  VOLCANIC   PHENOMENA 

"  slow  —  say  one  mile  a  week/'  He  observes  that  owing  to 
the  cooling,  and  the  partial  damming  thereby  along  the  front, 
the  hardened  upper  stratum  was  raised  by  the  descending 
stream  into  numerous  tumuli  of  various  forms  and  sizes  as  if 
by  pressure  from  above,  which  became  cones  or  domes,  and 
let  out  lavas  to  flow  over  the  surface  and  add  to  the  thick- 
ness ;  that  ''  upgushings"  also  occurred  through  fissures  ;  and 
that  thus  layer  was  added  to  layer,  increasing  the  thickness 
from  a  few  feet  to  fifty  or  a  hundred,  and  also  retarding  the 
progress  of  the  stream.  One  dome  on  the  stream  was  a 
hundred  feet  high  and  three  iiundred  feet  in  diameter ;  and 
through  the  fissured  top  and  sides  the  liquid  lavas  were 
visible,  and  easily  reached  by  the  pole  he  had  for  measuring 
the  thickness  of  the  cap,  —  two  to  five  feet.  These  effects 
were  especially  great  where  the  slope  was  very  small.  Pres- 
sure of  the  lavas  above,  and  gases  or  vapors  from  the  burning 
of  trees  and  other  vegetable  matter  l^uried  by  the  lavas,  are 
made  the  causes  of  the  uneven  surface  of  the  lava-stream. 

The  stream,  in  addition,  became  widened  by  the  lateral 
out-gushimi-s,  divided  into  a  number  of  channels,  and  shifted 
to  the  right  or  left.  After  flowing  freely  for  a  while,  the 
stream  often  suddenly  cooled  and  hardened  along  the  front 
and  remained  for  several  days  inactive  ;  "'  at  length,  immense 
areas  of  the  solidified  lava,  four,  five,  or  six  miles  above  the 
extremity,  are  again  in  motion,  cones  are  uncapped,  domes 
crack,  hills  and  ridges  of  scoria  move,  and  great  slabs  of  lava 
are  raised  vertically  or  tilted  in  every  direction." 

On  the  22d  of  October,  1856,  the  stream  was  within  five 
miles  of  the  sea-coast  north  of  Hilo,  still  pushing  out  and 
spreading  itself.  Mr.  Coan  says  that  the  lavas  were  even 
then  flowing  in  the  tunnel-ways  from  the  place  of  outbreak 
to  the  lower  extremity,  although  no  fires  were  seen,  —  evi- 
dently an  opinion  rather  than  a  direct  observation.  He 
argues  for  the  absence  of  fissures  beneath  the  stream  for  the 
supply  of  lava,  from  the  absence  of  steaming  vents  and  cones. 


IN   THE   HISTORY   OF    MOUNT    LOA.  191 

After  fifteen  months,  in  November,  the  fires  ceased  action. 
The  stream  includes  many  square  miles  of  aa  and  immense 
fields  of  pahoehoe. 

1859,  Great  Eruption  commencing  Januaey  23.  —  Prof. 
R.  C.  Haskell  (of  a  party  to  the  place  of  eruption  including 
also  Professor  Alexander  and  President  Beckwith)  reports^ 
that  on  the  23d  ''smoke"  was  seen  over  the  summit  from 
Waimea  by  Mr.  Lyons  of  that  place.  In  the  evening  lavas 
were  ejected,  and  the  light  was  bright  enough  at  Hilo,  thirty- 
five  miles  east,  to  read  Hue  print.  ''  No  earthquake  was  felt 
in  any  part  of  the  island."  But  dead  fish,  apparently  par- 
boiled, were  found  in  the  sea  to  the  northwestward,  both 
east  of  Molokai  and  between  Molokai  and  Oahu. 

The  stream  flowed  northwestward  by  the  foot  of  Hualalai, 
"  turning  just  enough  northward  to  fetch  by  the  northeastern 
flank  of  this  mountain,"  and  reached  the  sea  on  the  31st  of 
January  at  Wainanalii,  a  dozen  miles  south  of  Kawaihae,  a 
distance  in  all  of  thirty-three  miles  in  eight  days.  The  chief 
source  was  probably  about  10,500  feet  above  the  sea-level. 
Above  this  point,  for  four  miles,  a  fissure,  two  inches  to  two 
feet  wide,  descends  the  mountain,  from  which  some  lavas 
escaped.  Several  cinder-cones  stand  along  the  line  of  fis- 
sures, and  two  of  them  near  its  extremity.  Half  a  mile 
farther  down  the  outflow  began. 

The  lavas,  "white  hot"  as  they  escaped,  were  thrown  at 
once,  as  at  the  1852  eruption,  into  a  fountain,  the  height  of 
which,  according  to  Mr.  Vaudrey,  who  happened  to  be  on  the 
mountain  at  the  outbreak,  was  three  or  four  hundred  feet. 

On  the  9th  of  February  the  issuing  lavas  were  ''  at  a  white 

1  Haskell,  American  Journal  of  Science,  1859,  xxviii.  66,  284  (the  latter  from 
letter  of  June  22) ;  1860,  xxix.  301,  letter  of  November  5.  There  are  shorter  reports 
by  the  Editor  of  the  "Commercial  Advertiser"  of  Oahu,  and  Eev.  L.  Lyons,  Ibid., 
1859,  xxvii.  412  ;  and  Coan,  Ibid.,  xxvii.  415,  letter  of  Feb.  2,  1859,  and  xxix.  302, 
letter  of  Nov.  25,  1859.  W.  L.  Green,  Vestiges  of  the  Molten  Globe,  1887,  pp.  163, 
270,  280. 


192  VOLCANIC  php:nomena 

heat  and  apparently  as  liquid  as  water."  The  report  says 
that  the  stream  below  dashed  along  in  cataracts  and  rapids 
at  such  a  rate  that  "  the  eye  could  scarcely  follow  it."  For 
eight  to  ten  miles  there  was  a  succession  of  cascades  and 
rapids,  some  of  them  a  consequence  of  obstructions  met  on 
tlie  way  and  others  due  to  the  obstructions  which  the  stream 
made.  The  lava  flowed  more  gracefully  than  water  and  with 
great  velocity,  following  the  surface  beneath,  rising  as  it  rose, 
and  turning  abruptly,  with  the  outside  of  the  stream  higher 
than  the  inside,  the  mobility  being  perfect. 

Both  pahoehoe  and  cm  were  formed.  The  aa  portions  are 
described  by  Professor  Haskell  as  produced  by  deep  lava- 
streams,  —  streams  flowing  sluggishly  where  the  slopes  are 
small,  which  become  dammed  up  in  front  by  the  cooling,  by 
the  breaking  up  of  the  cooled  barrier  and  crust,  and  by  the 
rolling  over  and  over  of  the  stream.  Often  at  the  end  of  the 
aa  stream  no  liquid  lava  could  be  seen,  and  the  only  motion 
was  the  rolling;;  of  the  iag^sfed  rocks  of  all  sizes  down  the  front 

O  J      CO 

of  the  embankment.  Sometimes  it  broke  through  the  em- 
bankment, and  flowed  on,  '^  carrying  jagged  rocks  of  all  sizes 
on  its  back,  which  looked  like  hills  walking  ;  "  then  it  became 
clogged  again,  with  finally  a  repetition  of  the  process  of 
breaking  up  and   piling. 

The  stream,  after  reaching  the  seashore,  continued  flowing 
into  the  sea  till  after  the  25th  of  November.  The  surface  of 
the  stream  was  of  black  hardened  lavas  ;  but  at  the  sea- 
border  the  liquid  lavas  ran  out  at  a  red  heat,  having  flowed 
under  cover.  Professor  Haskell  states,  for  at  least  twenty-five 
miles,  if  not  from  the  source. 

According  to  Mr.  W.  L.  Green,  the  column  of  vapor  that 
rose  from  the  orifice  or  crater,  alongside  of  which  his  tent 
was  pitched,  was  five  hundred  feet  wide  and  ten  thousand 
feet  high.  He  says  :  "•  From  the  whole  interior  of  this  crater 
rose  the  great  illuminated  column  of  smoke  perpendicularly, 
and  then  at  a  great  height  in  the  atmosphere  it  spread  out  on 


IN    THE    HISTORY   OF   MOUNT   LOA.  193 

all  sides."  It  continued  for  many  weeks,  but  ceased  before 
the  flow  was  ended.  Tlie  lava  appeared  to  have  broken  out 
at  the  intersection  of  two  fissures.  Over  the  surface  in  the 
vicinity  there  was  a  thick  deposit  of  "  pumice  "  or  *•'  glass- 
foam."  The  top  of  the  mountain  at  the  time  was  covered 
with  snow,  —  a  source  of  percolating  water.  While  Mr. 
Green  was  near  the  stream,  on  the  plain  between  Loa,  Kea, 
and  Hualalai,  "  loud  explosions  were  heard  all  night  long, 
like  the  reports  of  heavy   cannon." 

Mr.  Green  also  states,  from  his  observations,  that  at  the 
seashore  the  lava  ran  over  a  low  shelf  about  ten  feet  high 
and  five  or  six  hundred  feet  wide,  and  fell  into  the  sea  where 
the  water  was  twenty  or  thirty  feet  deep.  "  It  came  from 
under  the  crust  in  great  red-hot  flattened  spheroidal  masses, 
having  something  the  appearance  of  moderately  thick  por- 
ridge as  it  is  poured  from  a  saucepan,  —  the  spheroidal  masses 
perhaps  ten  to  fifteen  feet  wide  and  four  to  six  feet  deep.  .  .  . 
There  was  no  steam,  vapor^  or  gas  whatever  to  be  seen 
coming  from  the  lava  until  it  went  under  water.  Indeed, 
the  first  contact  of  the  red-hot  spheroids  did  not  seem  to  pro- 
duce a  particle  of  steam,  and  it  was  only  when  each  had  gone 
under  water  and  become  partially  cooled  off  that  a  puff  of 
steam  rose  above  the  water,  .  .  .  an  effect  due  to  the  sphe- 
roidal state  of  the  water  against  the  red-hot  surface." 

No  sympathy  was  exhibited  by  Kilauea.  Mr.  Coan  says : 
''  We  have  occasional  earthquakes,  —  two  in  February,  one 
in  July,  and  two  in  November  of  the  current  year  (1859)." 

In  June,  according  to  Professor  Haskell,  there  was  no 
action  in  the  summit  crater. 

1864,  August  5.  —  Mr.  W.  T.  Brigham  found  the  sunnnit 
crater,  at  this  date,^  without  any  signs  of  action  excepting 
some  "  steam  issuing  from  the  northern  bank."  There  were 
two  cones  at  bottom,  about  two  hundred  feet  high,  near  the 

1  Memoir,  p.  384. 
25 


194  VOLCANIC   PHENOMENA 

east  side.  He  also  observes  that  in  various  places  over  the 
great  plain  about  the  crater  there  ^'  were  large  irregular 
masses  of  a  solid  reddish  clinkstone,  much  used  for  stone 
axes,"  and  speaks  of  the  "  hard  compact  graystone  of  the 
summit  and  walls." 

\^Qb,' December  30.  —  Light,  says  Mr.  Coan,  was  seen  "at 
the  very  summit,"  on  the  night  of  the  SOtli  of  December.^ 
It  continued,  with  variations  in  intensity,  sometimes  very 
brilliant,  at  others  faint  or  gone,  for  four  months,  or  until  the 
last  of  April,  or  perhaps  into  May.  Mr.  Richardson,  propri- 
etor of  the  Volcano  House,  reported  tlie  occasional  escape  of 
steam,  but  no  outflow  of  lava  is  known  to  have  occurred. 
"  The  falls  of  snow  on  the  mountains  this  winter  have  been 
frequent  and  heavy,  extending  almost  to  their  bases."  No 
earthquakes  were  reported.  "As  it  was  winter,  no  one 
ascended  the  mountain."  In  May  a  great  increase  of  ac- 
tivity began  in  Kilauea. 

1868,  Great  Eruption  commencing  in  Earthquakes, 
March  27.  —  On  March  27,  Friday,  many  slight  earthquakes 
were  felt  in  Kau,  southern  Hawaii,  and  in  Kona,  the  south- 
western district.  On  the  28th  they  were  more  energetic  and 
frequent,  and  extended  east  to  Hilo,  and  northward  through 
Kona.  Mr.  T.  D.  Paris,  of  Kealakekua,  South  Kona,  reports^ 
that  on  the  morning  of  Friday  fire  and  great  columns  of 
"  smoke  "  were  seen  at  the  summit ;  and  on  Saturday  the 
28th  the  fires  were  visible  from  Hilo,  according  to  Mr.  Coan.^ 
Mr-  F.  S.  Lyman  reports,  from  Kau,  that  the  first  outbreak 
was  a  little  to  the  southwest  of  the  summit ;  that  others  fol- 
lowed, and  soon  the  lavas  were  seen  in  four  streams  running 
down  the   mountain  in  a    southerly  and  easterly  direction. 

^  Coan,  American  Journal  of  Science,  1866,  2d  series,  xli.  424,  letter  of  Feb.  27, 
1866;  and  xliii.  264,  1867,  letter  of  August  31,  1866. 

^  Paris,  American  Journal  of  Science,  1868,  2d  series,  xlvi.  107. 

8  Coan,  Ibid.,  p.  106  ;  F.  S.  Lyman,  Ibid.,  p.  109;  H.  M.  Wliitney,  Ibid.,  p.  112. 


IN   THE   HISTORY    OF   MOUNT   LOA.  195 

By  Sunday  (the  oOth)  the  line  of  smoke  had  advanced  about 
fifteen  miles  on  a  line  toward  Captain  Brown's  house  in 
Kahuku.  (See  southern  part  of  map  of  Hawaii.)  But  the 
light  of  the  summit  had  disappeared  ;  it  was  not  seen  at 
Hilo  after  the  28th. 

During  this  time,  however,  the  earthquakes  became  still 
more  violent  and  destructive,  and  almost  continuous.  On 
Thursday,  April  2,  at  four  p.  m.,  occurred  ''  the  terrible 
shock,"  destroying  houses  and  life,  making  fissures  of  great 
length  and  depth,  dislodging  rocks,  and  half  a  mile  in  breadth 
of  marshy  earth  from  the  mountain  side  of  Kapapala,  to  the 
destruction  of  a  native  village,  besides  raising  earthquake 
waves  on  the  southern  coast,  that  swept  away  the  villages  of 
Punaluu,  Ninole,  Kawaa,  and  Honuapo.  The  position  of  the 
land-slide  is  shown  on  tlie  map  of  Hawaii  (Plate  I.).  It  was 
also  violent  to  the  eastward  in  Hilo,  the  only  stone  building 
being  thrown  down,  and  furniture  in  other  houses  ;  but  so 
light  on  Oahu,  two  hundred  miles  to  the  westward,  that  most 
of  the  inhabitants  of  Honolulu  were  unaware  of  it,  those  in 
stone  houses  being  almost  the  only  persons  that  felt  it. 

On  the  Tth  of  April  the  lava  escaped  from  a  wide  fissure 
in  the  district  of  Kahuku,  ahout  fifty-six  hundred  feet  above 
the  sea-level.  Along  the  fissure,  in  the  course  of  a  mile,  the 
escaping  lavas  were  thrown  into  four  fountains,  which  were 
playing  on  the  lOtli,  when  the  place  was  visited  by  Mr.  H.  M. 
Whitney,  of  Honolulu.  According  to  this  writer's  descrip- 
tion, the  fountains  rose  to  a  height  of  five  to  six  hundred 
feet,  along  the  line  of  the  fissure  for  a  mile.  The  lavas  were 
"blood-red,  yet  as  fluid  as  water."  Sometimes  two  of  the 
fountains  joined,  and  then  all  four  were  united.  At  one  time 
they  subsided  for  a  few  minutes,  and  then  burst  out  again 
and  went  to  a  height  of  a  thousand  feet.  Large  stones  and 
rocks  were  thrown  up.  some  weighing  a  hundred  tons  ;  and 
so  many  that  they  seemed  to  fill  the  air.  The  lava  of  the 
fountains  is  stated  to  have  had  a  rotation  "  to  the    south." 


196  VOLCANIC   PHENOMENA 

Below  the  fountains  the  lava  flowed  in  a  rapid  stream  to  the 
sea,  making  a  descent  of  two  thousand  feet,  and  reaching  the 
shore  in  two  hours.  The  rate  of  flow  is  stated  to  have  been 
ten  to  twenty-five  miles  an  hour.^  A  cinder  or  tufa  cone  was 
made  at  tlie  place  of  discharge  into  the  sea,  which  was  first 
an  island,  and  afterward  became  joined  to  the  land  by  the 
flowing  lava.  The  eruption  ceased  in  the  night  between  the 
11th  and  12th,  after  only  five  days'  activity.  The  lava  is 
mostly  pahoehoe,  with  some  areas  of  aa,  and  extremely  chryso- 
litic.  At  the  crack  above  the  main  outburst,  the  lava  which 
escaped  was  light  l^rownish  scoria,  which  was  drifted  by  the 
winds,  along  with  much  capillary  glass.  The  season  was  one 
of  unusual  rains  over  the  mountain. 

Prof.  C.  H.  Hitchcock  examined  the  region  of  eruption  in 
June  of  1885,  both  above  and  below  the  extremity  of  thp 
pali  (precipice)  represented  on  the  map  (Plate  I.)  as  running 
along  Ijy  the  west  side  of  the  lava-stream.  He  states  the 
following  facts  to  the  author  in  a  letter  of  May  30,  1888 : 
The  fissure  whence  the  lavas  of  1868  flowed,  is  in  exact 
continuation  of  the  pali,  up  the  mountain.  I  traced  it 
fully  three  miles.  For  much  of  the  way  it  makes  a  narrow 
cafion  forty  to  fifty  feet  wide  at  the  maximum,  and  so  deep 
that  it  is  dangerous  to  explore  it.  In  the  lower  part  heat 
was  still  evident.  The  fissure  is  most  prominent  where  the 
lava  is  in  greatest  amount.  Its  borders  have  the  smoothed 
appearance  that  would  result  from  an  outflow  of  lava  over  its 
edge.  The  very  uppermost  point  reached  we  estimated,  from 
our  aneroid,  to  Idc  thirty-one  hundred  feet  above  Mr.  Jones's 
ranch  near  the  north  end  of  the  pali.  There  is  no  cone  at 
tliat  point,  as  there  is  at  the  sources  of  the  1855  and  1881 
tiows  which  I  also  visited.     Every  fact  harmonizes  with  the 

'  Pacific  Commercial  Advertiser  of  May  9,  1868.  See  also  W.  L.  Green's 
Vestiges  of  the  Molten  Globe,  pp.  294-303.  Mr.  Green  does  not  intimate  that 
Mr.  Whitney's  description  is  exaggerated.  According  to  Rev.  E.  P.  Baker,  the 
highest  fountain,  on  the  estimate  of  an  observer,  Mr.  Swain,  was  not  over  two  hun- 
dred feet. 


IN   THE   HISTORY   OF   MOUNT   LOA.  197 

view  of  a  rent  three  miles  long,  allowing  the  accumulated 
lava  to  discharg-e  in  one  or  two  davs'  time,  instead  of  oozino; 
out  of  a  single  small  orifice  for  months.  The  connection  of 
the  fissure  with  the  pali  shows  clearly  the  existence  of  a  fis- 
sure along  its  whole  length,  which  has  been  the  seat  of  erup- 
tions in  ages  past.  This  Kahuku  flow  was  analogous  to  that 
of  Kilauea  in  1840. 

2.    Eruptions  of  Mount  Loa  from  18G8  to  1890. 

1870,  Januarii  1.  —  During  the  first  two  weeks  of  January 
much  "  steam  and  smoke  "  arose  from  the  summit  crater.^ 
In  the  course  of  the  preceding  month  Judge  Hitchcock,  of 
Hilo,  with  others,  visited  the  crater,  and  found  much  escap- 
ing steam  but  no  visible  fires.  Slight  shocks  of  earthquakes 
often  occurred,  sometimes  one,  two,  or  three  a  day. 

1870.  —  Mr.  Severance  (as  I  learned  from  Rev.  E.  P. 
Baker,  of  Hilo)  was  at  the  summit  crater  in  1870,  and  found 
no  action  there. 

1872,  August  10.  —  On  the  night  of  the  10th  of  August, 
says  Mr.  Coan,^  "  a  lofty  pillar  of  light,"  two  thousand  feet 
high,  —  which  means  lighted  vapors  of  this  height,  —  stood 
over  the  sunnnit  crater,  with  varying  brilliancy,  indicating 
active  fires  within.  The  crater  was  ''  in  full  blast  on  the 
27th,"  and  continued  so  into  September.  On  the  23d  of 
August  a  tidal  wave  was  felt  on  the  coast  at  Hilo,  the  wa- 
ters during  a  calm  rising  four  feet,  and  in  a  second  wave, 
six  minutes  later,  three  feet,  and  diminishing  for  about  four- 
teen oscillations.  It  may  have  been  part  of  the  Mount  Loa 
disturbance ;  but  Kilauea  also  was  unusually  active  over  its 
Ulterior.     No  earthquake  is  reported. 

^  Coan,  American  Journal  of  Science,  1870,  xlix.  393,  letter  of  Jan.  24,  1870, 
2  Ibid.,  1872,  3d  series,  iv.  406,  letter  of  August  27,   1872,  and  1873,  v.  476, 
letter  of  Feb.  14,  1873. 


198  VOLCANIC   PHENOMENA 

The  "Pacific  Commercial  Advertiser,"  of  September  21,^ 
reports  an  ascent  to  tlie  summit  made  just  before  this  date. 
Near  the  southwest  corner  of  the  crater  tliere  was  a  foun- 
tain of  lava  about  seventy-five  feet  m  diameter,  playing,  it  is 
stated,  to  a  height  of  five  hundred  feet.  The  basin  from 
whicli  it  rose  covered  about  a  third  of  the  bottom,  and  was 
at  the  top  of  a  low  cone  made  by  the  falling  lavas.  Mr. 
J.  M.  Lydgate  has  informed  me  that  he  was  at  the  crater  in 
the  latter  part  of  August,  and  that  the  fountain  was  then 
in  play. 

1873,  January  6  aiid  7.  —  On  the  6th  of  January  the 
action  at  the  summit,  as  seen  from  Hilo,  was  "  marvellously 
brilliant,"  the  lighted  vapors  visible  at  night  rising  thousands 
of  feet  above  the  summit.^  There  was  evidence,  apparently, 
of  active  ebullition  or  a  playing  fountain  ;  and  this  conclu- 
sion is  favored  by  the  fact  that  the  herdsmen  of  Reed  and 
Richardson's  ranch,  at  Ainapo,  on  the  eastern  slope  (forty- 
two  hundred  feet  above  the  sea),  stated  that  the  mountain 
was  •'  constantly  quivering,  like  a  boiling  pot."  The  action 
suddenly  ceased,  without  any  known  outflow ;  the  time  of 
ending  the  display  is  not  mentioned.  Kilauea  had  been  very 
active  for  months.  No  earthquake  is  spoken  of,  and  no  sym- 
pathy with  Kilauea  implied. 

1873,  1874.  Brilliant  Summit  Displays  from  April  20, 
1873,  to  the  Autumn  of  1874.  —  The  summit  display  of  Jan- 
uary was  followed,  on  April  20,  three  months  later,  by  a 
return  to  activity,  or  to  a  degree  of  activity  that  was  visible 
from  Hilo.  Mr.  Coan  observes  that  the  lofty  columns  of 
light  above  the  summit  at  night  and  of  clouds  by  day  were 
proof  of  violent  ebullition  within  the  crater. 

1  Coan,  American  Journal  of  Science,  1872,  iv.  331,  and  407,  408. 

2  Ibid.,  1873,  V.  476,  letter  of  Feb.  14,  1873  ;  1874,  vii.  516  ;  1877,  xiv.  68. 
In  the  first  of  these  notices  the  date  given  is  January  27  ;  in  the  others,  January  6 

and   7. 


IN   THE   HISTORY   OF   MOUNT    LOA.  199 

On  the  6th  of  January,  1874,  Mr.  Coan  writes^  that  for 
nine  months  the  action  within  the  great  crater  has  not  re- 
mitted. "The  great  marvel  is  its  duration,"  without  any  out- 
side results.  There  appears  to  have  been  a  turn  of  sjDecial 
brilliancy  in  January.  On  the  following  October  (the  6th) 
he  says  ^  the  action  has  continued  "  for  eighteen  months,  and 
the  most  of  the  time  it  has  been  violent.  But  of  late  it  has 
become  more  quiet,  and  there  is  a  prospect  that  it  will  soon 
cease."  He  adds  :  "  We  have  had  few  earthquakes  during  the 
year,  and  these  have  been  feeble.  .  .  .  Kilauea  all  this  time 
was  unusually  active ; "  but  no  sympathy  with  Mount  Loa 
was  observed. 

It  is  of  great  importance  to  the  history  that  we  have  trust- 
worthy rejDorts  with  regard  to  the  condition  of  the  interior 
of  the  summit  crater  on  three  of  the  days  during  this  era  of 
prolonged  activity.  And  as  the  first  of  the  three — the  6th  of 
June,  1873  —  was  a  day  of  feeble  summit  light  as  seen  from 
below,  it  affords  data  for  an  estimate  of  its  condition  dur- 
ing times  of  greater  brilliancy.  The  explorer,  Miss  Bird,^ 
was  at  the  summit  on  the  6th  of  June,  and  describes  well 
the  condition  of  the  crater.  For  the  most  part  its  floor 
was  an  area  of  solid  black  lava  ;  but  at  one  end  (the  south- 
west ?)  there  was  "  a  fountain  of  yellow  fire,"  one  hundred 
and  fifty  feet  broad,  which  played  in  several  united  but 
independent  jets  to  a  height  of  one  hundred  and  fifty  to 
three  hundred  feet.  The  party  for  the  two  days  preceding 
had  been  under  the  impression  that  the  fires  had  faded  out ; 
and  yet  this  fire-fountain  was  all  the  time  in  action.  When 
within  two  miles  of  the  crater,  monitions  of  the  activity  were 
apparent  in  a  distant  vibrating  roar;  and  on  reaching  the  cra- 
ter edge,  the  roar  was  like  that  of  an  ocean,  rising  and  falling 

^  Coan,  American  Journal  of  Science,  1874,  vii.  516,  letter  of  Jan.  6,  1874. 

2  Ibid.,  1874,  viii.  467,  letter  of  Oct.  6,  1874  ;  and  1877,  xiv.  68,  letter  of 
March   17,  1877. 

^  Six  Months  in  the  Sandwich  Islands,  by  Isabella  L.  Bird,  London,  1876, 
pp.  266-273. 


200  VOLCANIC    PHENOMENA 

''  like  the  thunder-music  of  windward  Hawaii,"  —  a  compari- 
son used  also  by  Mr.  Kinney  in  describing  the  eruption  of 
1852.  At  night  the  lake  was  for  the  most  part  at  white 
heat,  and  its  surface  v/as  agitated  with  waves  of  white-hot 
lava  about  the  fountain  at  the  centre.  Through  the  rest  of 
the  vast  crater  the  projecting  ledges  were  thrown  into  bold 
relief  by  the  reflected  light,  and  by  numerous  dashes  and 
lines  of  fire  from  apertures  and  crevices.  Occasional  detona- 
tions were  heard,  but  no  shakings  except  the  tremors  from 
the  throw  and  fall  of  the  lavas.  At  one  time  the  jets,  after 
long  playing  at  a  height  of  three  hundred  feet,  suddenly  be- 
came quite  low,  and  for  a  few  seconds  there  were  "  cones  of 
fire  wallowing  in  a  sea  of  light,"  —  a  description  that  not 
only  reads  well,  but  I  feel  sure  is  to  the  life,  like  the  most  of 
Miss  Bird's  word-pictures  ;  then,  "  with  a  roar  like  the  sound 
of  gathering  waters,  nearly  the  whole  surface  of  the  lake  was 
lifted  up,  by  the  action  of  some  powerful  internal  force,  and 
its  whole  radiant  mass  rose  tliree  times  in  one  glorious  up- 
ward burst,  to  a  height,  as  estimated  by  the  surrounding 
cliffs,  of  six  hundred  feet.  .  .  .  After  this  the  fountain  played 
as  before."  "'  Tn  one  place  heavy  white  vapor  blew  off  pow- 
erful jets  from  the  edge  of  the  lake,  and  elsewhere  there 
were  frequent  jets  and  ebullitions  of  the  same ;  but  there 
was  not  a  trace  of  vapor  over  the  burning  lake  itself." 

In  "  The  Vestiges  of  the  Molten  Globe "  (p.  166),  Mr. 
W.  L.  Green,  with  whom  Miss  Bird  made  her  ascent,  gives 
confirmatory  facts.  He  makes  the  height  of  the  fountain 
generally  three  to  four  hundred  feet,  as  estimated  from  the 
known  depth  of  the  crater  ;  and  occasionally  some  spires 
shot  up,  he  observes,  to  a  greater  altitude.  He  adds : 
"•  Among  the  varied  forms  of  the  fountain  there  were  the 
low  rounded  dome ;  a  spire  at  centre,  with  a  fountain  either 
side  in  the  form  of  a  wheat- sheaf  ;  and  one  great  wheat- 
sheaf."  Besides  a  dull  roar,  there  was  "  the  metallic  clink  " 
from  the  fall  of    masses   of  lava  of  the   fountain  which  were 


IN   THE   HISTORY   OF   MOUNT   LOA.  201 

cooled  in  the  air;  these  cooled  fragments  formed  a  light 
falling  veil  over  the  dazzling  fountain,  and  descending  into 
the  lake  outside  of  the  jets,  made  a  scum  over  its  surface. 
Only  a  light  vapor  was  seen  over  the  playing  fountain. 

Early  in  August,  1873,  Dr.  0.  B.  Adams  ascended  Mount 
Loa,  at  a  time  when  the  light  at  the  summit  was  unusually 
brilliant.  He  found  the  fountain  playing,  he  says,  to  a  height 
of  two  to  five  hundred  feet,  and  "  assuming  all  the  forms 
of  a  grand  fountain  of  water."  ^ 

In  October,  1873,  Messrs.  E.  G.  and  H.  R.  Hitchcock  spent 
one  night  at  the  summit  near  the  site  of  Wilkes's  camp,  on 
the  east  side  of  the  central  crater  or  pit.  They  state  that 
a  fountain  of  lava  was  playing  in  the  southwestern  end  of 
the  crater,  to  a  height  of  six  hundred  feet,  this  height  being 
obtained  by  lying  upon  the  brink  and  looking  across  the 
pit  to  the  top  of  the  opposite  wall  ;  •'  the  column  of  fire 
ascended  at  least  one  half  higher  than  the  distance  from 
the  floor  to  the  top  of  the  walls,  and  taking  this  distance 
at  four  hundred  feet,  the  height  of  the  fountain  was  de- 
cided to  be  approximately  six  hundred  feet."  The  descend- 
ing lava  of  the  fountain,  falling  into  the  basin,  flowed  off 
northward  nearly  the  whole  length  of  the  western  side  of 
the  pit.^ 

1875,  January.  —  Mr.  W.  L.  Green  mentions  the  occur- 
rence of  summit  action  at  this  time  for  a  month,  in  his 
tabular  statement  of  eruptions,  and  says  nothing  of  one  in 
August  of  this  year,  to  which  date  Mr.  Coan  refers  the  1875 
eruption.  The  report  of  the  "  Challenger,"  mentioned  beyond, 
sustains  Mr.  Coan's  statement,  but  does  not  positively  set 
aside  that  of   Mr.  Green. 

1  Hawaiian  Gazette,  Sept.  3,  1873. 

*  Letter  of  W.  C.  Merritt,  in  American  Journal  of  Science,  1889,  xxxvii.  51. 

26 


202  VOLCANIC   PHENOMENA 

1S76,  August.  —  Mr.  Coan  says  :  ^  "I  think  it  was  on  the 
11th  of  August  that  the  summit  crater  was  again  in  bril- 
liant action.  The  action  continued,  as  appeared  in  the  view 
from  Hilo,  for  one  week,  and  without  any  observed  evidence 
of  an  outflow." 

In  the  first  half  of  August,  the  day  not  stated,  a  party  from 
the  "  Challenger  "  Expedition  visited  Kilauea.  As  reported 
in  the  first  volume  of  the  ''  Scientific  Results  of  the  Expedi- 
tion" (p.  766),  "a  globular  cloud"  was  seen  over  the  summit 
of  Mount  Loa,  which  was  '•  perpetually  re-formed  by  con- 
densation," and  had  "  a  brilliant  orange  glow  at  night,  look- 
ing as  if  a  fire  were  raging  in  the  distance."^ 

1876,  February  13.  —  Another  grand  display  from  the  sum- 
rait  crater,  but  of  short  duration.     No  outflow  is  reported.^ 

1877.  Probable  Submarine  Eruption,  February  14.  — 
The  display  of  light  on  the  14th,  says  Mr.  Coan,*  was  "  most 
glorious."  The  columns  of  illuminated  steam  rose  "  with 
fearful  speed  to  a  height  of  fourteen  to  seventeen  thousand 
feet,  and  then  spread  out  into  a  vast  fiery  cloud,  looking  at 
night  as  if  the  heavens  were  on  fire."  The  brilliancy  con- 
tinued only  ten  days. 

No  outflow  is  positively  known  to  have  occurred,  but  it  is 
probable  that  a  submarine  discharge  took  place  off  western 
Hawaii.  The  steamer  brought  passengers  from  Honolulu  to 
visit  the  mountain,  but  returned  as  the  fire  had  disappeared. 
But  before  the  vessel  was  fairly  out  of  sight  of  land,  "  a  re- 
markable bubbling  was  seen  in  the  sea  about  three  miles 
south  of  Kealakekua,  a  mile  from  the  shore,"  and  steam  and 
scoria  were    thrown   up.     Mr.   H.   M.   Whitney  states  that 

1  Coan,  American  Journal  of  Science,  1877,  xiv.  68,  letter  of  March  17,  1877. 
^  See  also  Moseley's  Notes  by  a  Naturalist  of  the  "  Challenger,"  London,  1879, 
p.  500. 

'  Coan,  American  Journal  of  Science,  1877,  xiv.  68,  letter  of  March  17,  1877. 
*  Ibid. 


IN   THE   HISTORY   OF   MOUNT   LOA.  203 

^^  blocks  of  lava  two  feet  square  came  up  from  below,  strik- 
ing and  jarring  the  boats ;  "  and  "  nearly  all  the  pieces  on 
reaching  the  surface  were  red-hot ;  ...  as  soon  as  they 
became  cold  they  sank."  This  eruption  took  place  on  the 
24th  of  February,  the  day  the  light  disappeared  from  the 
summit.^ 

On  the  land  new  fissures  were  opened  in  the  mountain 
which  had  a  westward  course  toward  the  place  of  submarine 
disturbance.  An  earthquake  is  reported  as  having  been  felt 
in  the  fissured  region,  but  not  at  Kealakekua.  A  heavy  tidal 
or  earthquake  wave  occurred  about  this  time  along  the  coast 
of  Kona." 

188U,  May  1.  —  Early  in  the  morning  of  May  1  a  light 
was  seen  at  or  near  the  summit,  which  soon  after  became 
so  intense  as  to  illuminate  Hilo  at  night.  It  indicated  vio- 
lent activity,  and  led  to  an  expectation  of  a  great  eruption. 
But  clouds  obscured  the  mountain  for  a  few  days,  and  when 
they  disappeared,  the  light  was  gone.'^  On  the  3d  and  4th  of 
May  flocks  of  Pele's  hair  and  light  particles  of  volcanic  dust, 
drifted  by  the  wind,  fell  over  Hilo.  According  to  reports 
from  Puna  and  Kau,  the  action  had  not  ceased  by  May  6. 
Mr.  Brigham  states*  that  his  guide  was  at  the  summit  at 
the  time,  and  saw  boiling  lava  in  the  south  crater ;  and  that 
the  tops  of  the  jets  were  visible  to  the  native  while  he  was 
lying  down  some  distance  from  the  brink, — which  would 
make  the  height  of  the  jets,  Mr.  Brigham  says,  one  thou- 
sand feet.  As  the  depth  of  the  crater  was  not  over  eight 
hn.ndred  feet,  his  estimate  is  probably  too  high.  Mr.  Good- 
ale,  one  of  the  party  who  ascended  at  that  time,  reported,  as 

1  Hawaiian  Gazette,  Feb.  28,  1877. 

^  On  the  10th  of  May,  1877,  a  destructive  earthquake  wave  was  felt  at  the 
Hawaiian  Islands,  which  rose  at  Hilo  to  a  height  of  thirty-six  feet.  But  it  was 
of  South  American  origin,  where  there  were  heavy  earth-shocks,  aud  not  of 
Hawaiian. 

^  Ooan,  American  Journal  of  Science,  xx.  7,  letter  of  May  3-6,  1880. 

*  Brigham,  American  Journal  of  Science,  1888,  xxxvi.  33. 


204  VOLCANIC   PHENOMENA 

mentioned  in  a  letter  from  Mr.  E.  P.  Baker,  that  the  lavas 
were  thrown  sixty  or  eighty  feet  above  tlie  brink  of  the  crater 
on  which  the  party  were  standing ;  and  this  confirms  the  re- 
port of  the  native  guide. 

1880.  July  28.  — On  the  28th  of  July  Mr.  W.  T.  Brigham 
found  the  crater  without  action.^  The  walls  were  much  fis- 
sured about  the  southern  pit ;  fresh-looking  lavas  covered  the 
bottom ;  and  a  small  area  was  seen  on  the  west  border  of  the 
pit,  which  was  probably  of  recent  ejection.  Moreover,  about 
the  region  around  the  crater  there  was  much  of  the  spongy 
scoria,  some  masses  a  foot  in  diameter. 

1880,  1881.  Great  Eruption  from  Nov.  5,  1880,  to 
Aug.  10,  1881,  Nine  Months.  —  No  "violent  demonstrations 
or  earthquake"  announced  the  eruption.  The  first  light  was 
visible  in  the  evening  of  Friday  from  Waimea,  and  a  few  hours 
later  in  the  night  from  Hilo,  and  after  midnight  "  the  lavas 
could  be  distinctly  seen  leaping  like  a  fountain  into  the  air." 
The  next  day  a  line  of  light  extended  down  the  slopes  toward 
Mount  Kea,  from  a  point  about  eleven  thousand  one  hun- 
dred feet  above  the  sea.^  Near  the  same  time  another  stream 
flowed  from  the  source  southeastward  into  Kau,  and  soon 
after  the  lavas  commenced  a  third  stream  toward  Hilo,  be- 
tween those  of  1852  and  1855.  The  Kea  stream  stopped  on 
the  intermont  plateau  east  of  Kalaieha,  having  a  length  of 
ten  to  twelve  miles  ;  and  the  Kau  stream  reached  nearly  the 
same  length.  The  Hilo,  as  the  map  shows,  came  near  giving 
Hilo  a  burial.  As  observed  by  Judge  Hitchcock^  on  the  10th 
or  11th,  from  the  Kalaieha  Hills  at  the  south  foot  of  Mount 
Kea,  the    stream,   for   miles    northward    to  the    plain,   was 

*  Brigham,  American  Journal  of  Science,  1868,  xxxvi.  33. 

2  Coan,  Hitchcock,  Ibid.,  1881,  xxi.  79,  letter  of  Nov.  9-12,  1880;  xxii.  227, 
228,  letter  of  June  28  and  July  2!,  1881,  and  xxii.  322,  letter  of  August  24,  1881 ; 
Life  in  Hawaii,  p.  325. 

8  Ibid.,  1881,  xxi.  79,  and  xxii.  226. 


IN   THE  HISTORY   OF   MOUNT   LOA.  205 

a  continuous  belt  of  fire  in  steady  flow,  and  also  beyond  this 
for  several  miles  toward  Hilo.  The  regular  flow  was  inter- 
rupted half-way  from  the  plain  to  the  source  by  the  lavas 
rising  into  a  huge  dome,  from  which  they  flowed  over  like 
an  immense  fountain  ;  but  there  was  no  fountain  at  the 
source. 

Mr.  E.  S.  Baker  states,^  after  an  examination  of  the  region 
a  second  or  third  time,  in  July,  1888,  that  the  Kea  and  Kau 
streams  oris-inated  together  from 
the  same  source,  at  the  extremity 
of  a  long  fissure  where  there  is 
now  a  large  pit  crater,  called 
Puka  Uahi,  as  shown  at  S,  in 
the  annexed  figure  ;  and  that  the 
divergence  of  the  Kau  stream 
from  the  Kea  and  also  from  the 
Hilo  stream  was  owing  to  the 
fact  that  the  fissure  followed  the  course  of  a  "  divide,"  so 
that  a  small  obstacle  was  sufiicient  to  turn  the  flow  to  one 
side  or  the  other.  The  outflow  took  place  on  this  divide  ; 
the  Kau  stream  went  off  first  from  the  fissure,  or  at  least 
started  off  from  it  higher  up,  the  Kea  stream  next,  and  the 
Hilo  from  a  still  lower  point.  The  fissure  ran  by  the  north 
side  of  Red  Hill,  a  cone  with  a  deep  crater  which  was  still 
giving  out  vapors,  and  this  hill  was  apparently  the  occasion 
of  the  turn  southward  of  the  Kau  stream,  it  standing  at  the 
point  of  their  divergence.  This  Kau  stream  is  in  general 
aa,  but  near  the  source,  in  a  most  quiet,  unobtrusive  way,  the 
aa  changes  into  pahoehoe.  Near  the  head  of  the  Kau  stream 
there  is  a  cinder-cone,  named  '^  Little  Vesuvius "  (at  V  on 
the  map).  This  cone  and  the  pit-crater  were  also  steaming, 
although  seven  years  had  elapsed  since  the  end  of  the 
eruption. 

^  Baker,  letter  to  the  author,  and  also  American  Journal   of  Science,  1889, 
xxxvii.  53. 


206  VOLCANIC   PHENOMENA 

The  thickness  of  the  stream  in  its  lower  part,  as  deter- 
mined by  the  depth  of  the  holes  left  where  trees  had  been 
burned  off,  was  found  by  Mr.  Baker  to  be  in  two  such  places 
twelve  and  eighteen  feet. 

In  four  months  the  stream  was  within  seven  miles  of 
Hilo,  or  about  twenty-six  miles  long;  in  seven  and  tw^o 
thirds  months,  June  28,  within  five  miles ;  in  eight  and 
one  half  months,  July  18,  about  two  miles  ;  and  August 
10,  nine  months  after  the  outflow  began,  it  stopped  within 
three  fourths  of  a  mile  of  Hilo.  On  June  30,  the  movement 
just  beyond  the  Hilo  tufa-hills  (the  Halai  Hills)  was,  as 
stated  by  Mr.  D.  H.  Hitchcock,  about  seventy-five  feet  an 
hour. 

On  its  w^ay,  says  Mr.  Ernest  E.  Lyman,  "  the  lava-stream 
came  in  contact  with  a  stream  of  water,  flowed  into, 
blocked,  and  turned  it  out  of  its  course.  The  steam  form- 
ing under  it  caused  frequent  explosions.  I  saw  it  pass 
over  a  water-fall.  At  first  the  water  cooled  the  lava  suf- 
ficiently to  make  it  brittle,  and  it  fell  over  in  chunks  till 
it  had  formed  a  pile  as  high  as  the  fall ;  and  then  it  flowed 
over,  forming  a  flume  of  lava.  It  was  a  wonderful  sight  to 
see  the  water  and  the  liquid  lava  flowing  side  by  side."  ^ 
Plate  XI.  represents  another  cascade  in  the  same  stream,  two 
and  a  half  miles  above  Hilo,  and  about  half  a  mile  below  that 
described  by  Mr.  Lyman. 

In  a  communication  to  the  "  Commercial  Advertiser  "  for 
November  20,^  the  formation  of  the  aa  or  clinker  fields  is 
described  as  follows  by  Judge  Hitchcock :  "  The  whole 
broad  front  of  the  then  sluggish  stream  was  a  mass  of  so- 
lidified lava  twelve  to  thirty  feet  in  height,  moving  slowly 
along  by  breaking  and  bearing  onward  the  crusted  cover- 
ing ;  along  the  whole  line  of  its  advance  it  was  one  crash 


^  E.  E.  Lyman,  communicated  by  President  Merritt,  in  July,  1889. 
^  Hitchcock,  American  Journal  of  Science,  1881,  xxii.  228,  from  the  "Com- 
mercial Advertiser"  of  Honohihi. 


IN   THE   HISTORY   OF   MOUNT   LOA.  209 

of  rolling,  sliding,  tumbling,  red-hot  rock,  no  liquid  rock 
being  in  sight ;  there  were  no  explosions,  but  a  tremendous 
roaring,  like  ten  thousand  blast-furnaces  all  at  work  at 
once.  The  rough  blocks  lie  piled  together  in  the  wildest 
confusion,  many  as  large  as  ordinary  houses.  They  [clinker- 
fields]  form  only  when  the  movement  is  slow." 

While  at  Hilo  in  August,  1887,  the  author,  under  the 
guidance  of  Rev.  E.  S.  Baker,  of  Hilo,  visited  the  cooled 
lava-stream  of  1880-1881,  and  its  tunnel.  The  ropy  twisted 
lines  and  tapestry  folds  cover  much  of  the  surface  ;  and  some 
are  on  a  most  delicate  scale,  the  tapestry  hangings  (like 
that  of  page  117)  only  an  inch  wide,  and  varying  from  this 
diminutive  size  on  one  extreme  to  a  breadth  of  six  or  eight 
feet.  Three  or  four  miles  from  Hilo  the  lava-stream,  which 
had  consisted  of  pahoehoe,  became  rather  abruptly  an  aa 
stream.  At  the  junction  the  pahoehoe  was  very  much  broken, 
as  if  by  an  intermittent  flow  in  the  stream. 

The  cavern,  or  rather  tunnel,  of  the  stream  had  very 
smooth  sides,  and  in  part  a  literally  glazed  surface,  indicat- 
ing the  flow  of  the  lava ;  and  thore  were  long  parallel  lines 
of  mouldings^  due  to  the  same  cause.  One  of  the  lines  of 
mouldings  had  the  form  and  position,  along  the  side  of  the 
tunnel,  of  a  solid,  handsomely  modelled  bench,  showing  that 
the  mouldings  were  due  to  projecting  points  and  larger  pro- 
tuberances of  the  solid  lava  outside.  The  tunnel  had  a 
varying  height  of  four  to  eight  feet,  but  in  some  portions 
diminished  to  two  feet,  and  in  others  rose  to  ten  feet.  The 
general  width  was  about  thirty  feet ;  but  there  were  large 
lateral  expansions.  The  layer  of  rock  above  was  two  to  six 
feet  thick. 

In  some  undisturbed  parts  of  the  tunnel  there  were  thick- 
ets of  long,  slender,  grayish-black  stalactites,  like  pipe-stems 
in  size,  scarcely  tapering  at  all  except  at  the  extremity 
where  there  is  usually  a  short  irregular  twist  (Plate  XV.). 
Where  most  crowded  they  were  twenty  to  thirty  inches  or 

27 


210  VOLCANIC   PHENOMENA 

more  long,  and  one  every  six  or  eight  inches.  Over  the  floor 
beneath  eacii  there  was  an  irregular  column  of  stalagmite  of 
similar  nature,  consisting  of  a  heap  of  bent,  coalescing  stems, 
of  the  same  diameter,  varying  from  a  few  inches  to  hfteen  or 
eighteen  in  height.  The  stalactites  were  solid  for  the  most 
of  their  length  ;  but  still  many  parts  were  hollow  cylinders. 
A  pocket  lens  was  sufficient  to  show,  after  emerging  again 
to  daylight,  that  the  texture  of  the  stalactite  was  stony, 
like  the  lava,  and  contained  similarly  minute  crystals  of 
feldspar,  which  were  lath-shaped  on  a  surface  of  fracture; 
and  that  the  cavities  were  lined  with  glassy  crystals  and 
magnetite. 

I  am  informed  by  Mr.  Baker,  in  a  letter  dated  Hilo,  July  3, 
1889,  that  at  one  place  in  the  tunnel,  where  the  stalactites 
were  only  two  or  three  inches  long,  their  bent  extremities 
were  all  turned  one  way,  and  that  was  toward  a  blow-hole 
entrance  to  the  tunnel,  —  favoring  the  view,  as  he  says,  that 
a  draught  from  the  interior  outward  had  determined  the 
bending. 

1882.  —  In  this  year  (the  month  not  stated)  Capt.  C.  E. 
Button  made  his  visit  to  the  summit.^  He  found  "  no  vol- 
canic action  whatever,  .  .  .  not  even  a  wisp  of  steam  issuing 
from  any  point."  No  mention  is  made  of  any  cinder-cone 
at  the  bottom. 

1883,  February.  —  Prof.  C.  H.  Hitchcock  was  at  the  sum- 
mit on  the  15th,  and  found  no  activity.  "  A  snow-squall 
struck  us,  and  the  entire  floor  of  the  crater  was  ivhite  with 
snow. 

1885,  ^pn7.  — In  April,  1885,  Rev.  E.  P.  Baker  visited 
the  crater  and  descended  to  its  bottom.     It  was  all  quiet. 

1  Eeport,  p.  139. 

2  Letter  to  the  author  of  May  30,  1 888. 


IN   THE   HISTORY   OF   MOUNT   LOA.  211 

1885,  October.  —  In  October,  1885,  Rev.  J.  M.  Alexander 
made  a  survey  of  the  summit  crater  for  the  Government  Sur- 
vey.^ The  bottom  of  the  crater  was  mainly  flat,  and  covered 
with  fresh  lavas ;  it  had  two  cones  in  it,  as  represented  on 
the  map,  the  southwestern  a  hundred  and  forty  feet  high  and 
smoking ;  steam  was  rising  from  "  hundreds  of  cracks,"  but 
no  fires  were  visible.  In  the  depressed  area  or  terrace  to, 
the  north  of  the  central  or  main  pit  a  circular  pit-crater  was 
found,  as  shown  on  the  map,  which  was  six  hundred  feet 
deep  and  a  thousand  feet  wide,  and  had  a  cone  at  centre  that 
was  still  smoking.  Near  the  junction  of  the  central  pit  with 
the  south  crater  there  had  been  an  eruption  from  fissures  that 
were  still  steaming,  from  which  a  great  stream  had  flowed 
southwestward  in  the  Kahuku  direction ;  the  lava  had  also 
poured  down  in  cataracts  into  the  south  crater.  Mr.  Alex- 
ander observed  about  the  summit  for  a  breadth  of  a  fourth 
of  a  mile  from  the  crater  many  blocks,  from  fifty  pounds 
to  a  ton  in  weight,  of  a  "•  solid,  flinty  lavao"  The  dimen- 
sions of  the  crater  obtained  by  Mr.  Alexander  are  stated 
on  the  map  (Plate   X.). 

1887.  Gee  AT  Ekuption  in  January  and  February, 
ATTENDED  BY  EARTHQUAKES. — In  December,  1886,  earth- 
quakes became  frequent  in  southwestern  Hawaii.  By  the 
12th  of  January  the  shocks  averaged  three  a  day.  Between 
twelve  minutes  past  two  o'clock  on  the  morning  of  January 
17  and  four  o'clock  on  the  morning  of  the  18th,  314  shocks 
were  counted  by  Mr.  George  Jones  in  Kahuku,  sixty-seven 
between  the  latter  date  and  midnight,  and  three  the  follow- 
ing day.  In  Hilea,  ten  miles  west,  618  were  counted  between 
two  o'clock  on  the  morning  of  the  16th  and  seven  o'clock  on 
the  evening  of  the  18th. 

On  the  night  of  the  16th,  with  the  sudden  increase  in  the/ 

^  Alexander,  American  Journal  of  Science,  1888,  xxxvi.  35. 


212  VOLCANIC   PHENOMENA 

earthquakes,  fires  broke  out  at  the  summit  near  the  small 
crater  south  of  the  summit  crater,  Pohaku  o  Hanalei  (Plate  I.), 
and  in  a  few  hours  disappeared.  The  height  of  this  first  out- 
break, according  to  Mr.  E.  P.  Baker,  was  eleven  thousand 
five  hundred  feet.  On  the  18th,  at  seven  o'clock  in  the 
morning,  —  three  hours  after  the  cessation  of  the  earth- 
quakes, —  an  outbreak  took  place  in  Kau,  north  of  Kahuku. 
The  lavas  came  from  a  fissure  about  sixty-five  hundred  feet 
above  the  sea-level  and  twenty  miles  from  the  sea,  and  reached 
the  sea  at  noon  on  the  19th,  nearly  four  miles  west  of  the  flow 
of  1868.  It  extended  the  shore  outward  three  to  five  hun- 
dred feet  without  making  a  cinder-cone  on  the  sea-border. 
By  noon  of  the  24th  the  flow  had  stopped,  but  the  fires  were 
still  active  along  the  stream. 

At  the  outburst,  as  at  the  Kahuku  eruption  of  1868,  the 
lavas  were  thrown  up  into  fountains.  The  fountains  were 
about  eighty  feet  in  diameter,  and  eighty  to  a  hundred  or 
more  feet  in  height.  They  were  photographed ;  and  two  of 
the  views,  representing  the  same  part  of  the  stream  and  one 
fountain,  are  shown  on  Plate  XII.  Mr.  Spencer,  who  visited 
the  source  on  the  20th,  states  that  there  were  then  fifteen 
fountains,  and  that  the  highest  was  two  hundred  feet ;  others 
make  the  height  not  over  half  this  amount.  The  stream  is 
stated  to  have  flowed  away  bearing  bowlders  weighing  tons, 
with  explosions  at  intervals.  During  the  first  twenty-four 
hours  the  rate  of  flow  was  but  a  mile  and  a  half  an  hour,  and 
the  stream  made  was  of  aa ;  afterward  the  flow  was  rapid, 
and  the  stream  of  pahoehoe. 

The  earthquake  in  Kau  threw  down  walls  that  had  a 
northeast  and  southwest  direction,  —  the  throw  was  to  the 
southeast ;  and  light  wooden  houses  were  moved  eight  or  ten 
inches  in  the  same  direction  or  down  the  slope.  The  oscilla- 
tions in  Hilo  were  reported  to  have  been  from  south-southeast 
to  north-northwest. 

On  February  20  Mr.  D.  H.  Hitchcock  was  at  the  summit, 


w 


►=j 


.7   .'-i\ 


IN   THE   HISTORY  OF   MOUNT   LOA.  215 

and  found  the  crater  quiet,  but  vapors  issuing  from  large 
fissures. 

Kilauea  was  moderately  active  during  the  period  of  erup- 
tion, rather  increasing  in  activity  with  its  progress,  but 
without  evincing  special  disturbance  or  sympathy/ 

In  July,  1888,  going  from  Ainapo  to  the  source  of  the  erup- 
tion of  1887,  in  Kahuku,  about  six  thousand  feet  above  the 
sea-level.  Rev.  E.  P.  Baker  passed  through  regions  of  woods 
and  D-rass,  and  saw  seven  runnino;  streams  and  three  or  four 
ponds  of  water.  There  had  been  heavy  rains.  The  fissure 
of  1887,  about  four  hundred  feet  above  the  place  of  outflow, 
was  still  giving  out  vapors.  No  deep  crater  marked  the 
place  of  discharge.^ 

1887,  Dccemher  29. —A  letter  from  Mr.  J.  S.  Emerson, 
dated  Kohala,  Hawaii,  December  29,  states  that  the  view  of  the 
summit  of  Loa  from  that  place  indicates  activity  in  Mount 
Loa.  "  Volumes  of  smoke  and  steam  have  been  pouring  out 
of  the  summit  crater,  but  no  glow  or  reflection  of  fire  has 
been  observed.  .  .  .  The  summit  is  now  heavily  coated  with 
snow."  Another  letter  of  April  states  that  on  March  29, 
1888,  the  signs  of  activity  at  the  summit  had  disappeared ; 
the  exact  time  of  their  cessation  was  probably  early  in 
February. 

1888,  Jubj  18.  —  The  summit  was  visited  at  this  date  by 
President  W.  C.  Merritt  and  Rev.  E.  P.  Baker."  The  range 
of  the  thermometer  for  the  day  was :  At  noon,  62°  F. ;  at 
seven  o'clock  in  the  evening,  40°  F.  ;  at  eleven  o'clock  at 
night,  30°  F.  ;  at  daybreak,  26°  F.  Mr.  Merritt  states  that 
in  the  central  pit  of  Mokuaweoweo,  at  bottom,  a  small  cinder- 
cone  was  found  not  far  from  the  eastern  wall,  and  just  south- 

1  The  above  is  from  the  "  Pacific  Commercial  Advertiser  and  Hawaiian  Gazette" 
of  Honolulu  ;  American  Journal  of  Science,  1887,  xx.xiii.  310. 

2  Baker,  American  Journal  of  Science,  1889,  xxxvii.  53. 
8  Ibid.,  1889,  xxxvii.  51,  52. 


216  VOLCANIC   PHENOMENA. 

west  a  pumice-cone  in  the  midst  of  an  cm  flow,  the  summit  of 
which  was  very  hot  and  reddish  from  the  action  of  vapors. 
In  the  southwest  corner  of  the  pit  there  was  a  cone  (at  F  on 
map,  Plate  X.),  from  which  vapors  were  escaping,  and  south 
of  it,  at  m,  a  circular  pit  three  and  four  hundred  feet  in 
its  diameters  by  estimate,  and  a  hundred  and  fifty  to  a  hun- 
dred and  seventy-five  feet  deep.  In  the  walls  of  the  pit,  which 
consisted  of  the  edges  of  layers  of  basaltic  rock,  one  layer  was 
forty  to  fifty  feet  thick,  and  vertically  columnar  in  structure. 
The  floor  of  the  central  pit  had,  as  a.  whole,  a  slope  from  the 
southwest  to  the  northeast,  —  confirming  the  view  that  the 
southwest  part  of  the  pit  had  been  the  seat  of  greatest  activ- 
ity, as  it  is  in  Kilauea.  Southwest  of  m  the  outer  wall  of 
the  central  pit  was  cut  through  from  top  to  bottom  by  two 
parallel  fissures,  which  had  a  south-southwest  direction,  and 
thence  pointed  nearly  toward  the  place  of  chief  eruption  of 
1887.  East  of  m,  and  near  the  wall  in  the  direction  of  L, 
there  were  great  numbers  of  small  fumaroles,  from  which 
sulphur  vapors  were  escaping  freely,  and  large  deposits  of 
sulphur  had  been  made  about  them.  Near  h  two  dikes,  two 
to  two  and  a  half  feet  thick,  intersected  the  walls,  crossing 
one  another  at  a  small  angle,  the  rock  of  which  had  a  feld- 
spathic  aspect. 

From  a  rough  measurement  the  depth  of  the  crater  on  the 
east  side  was  made  not  over  three  hundred  and  fifty  feet.  If 
this  small  depth  is  sustained  by  careful  observations,  a  great 
change  of  level  had  taken  place  since  the  survey  of  Mr.  Alex- 
ander in  1885.  Such  a  change  might  have  been  among  the 
effects  of  the  eruption  of  February,  1887.  On  the  summit, 
to  the  south  of  the  crater,  Mr.  Baker  observed  six  parallel 
fissures,  ten  to  twenty  rods  apart,  having  a  course  toward 
the  place  of  eruption  of  1887. 


PKOGKESSIVE  CHANGES  IN  THE  MOUNT  LOA  CRATER.   217 


3.  General  Summary,  with  Conclusions. 

The  subjects  connected  with  Mount  Loa  and  the  summit 
crater  considered  in  the  following  summary  and  conclusions 
are  the  following  :  — 

1.  The  times  and  time-intervals  of  eruptions  and  of  summit 
iUicminations  or  activity,  with  reference  to  (1)  periodicity, 
(2)  relations  to  seasons,  (3)  variations  in  activity  since  1843, 
and  (4)  the  changes  in  the  depth  of  the  crater. 

2.  Tlie  ordinary  activity  ivithin  the  summit  crater. 

3.  Causes  of  the  ordinary  movements  wit! tin  the  crater. 

1.  Times  and  Time-intervals  op  Eruptions. 

Question  of  Periodicity.  —  Commencing  with  the  eruption 
of  1832,  there  have  been  nine  registered  eruptions  of  Mount 
Loa.  Their  times  and  heights  of  outflow,  directions  and 
lengths  of  stream,  and  relations  to  earthquakes  are  stated  in 
the  following  table  :  — 


Reported 
Earthquakes. 

Height  of  Chief 
Outflow. 

Direction  and 
Length  of  Flow. 

1.  1832,  June  20,  2-.3  weeks     .... 

None. 

Summit. 

No  outflow. 

2.  1843,  Jan.  9  to  end  of  Feb.,  U  mos.  . 

None. 

11,000. 

N.N.W.,15m. 

3.  1851,  Aug.  8,  for  3  or  4  days    .     .     . 

None. 

12,900. 

W.,  10  m. 

4.  1852,  Feb.  17  into  March,  20  days     . 

None. 

Little  over  10,000. 

E.,  20  m. 

5.  1855,  Aug.  11  to  Nov.,  1856,  15  mos. 

None. 

12,000. 

E.,  26  m. 

6.  1859,  Jan.  23  to  Nov.  25,  10  mos.  .     . 

None. 

10,500. 

N.  W.,  33  m. 

7.  1868,  March  27, 16  days 

Earthquakes. 

3,000. 

S.,  10-11  m. 

8.  1880,  Nov.  5  to  Aug.,  1881,  9  mos.     . 

None. 

11,100. 

E.,  30  m. 

9.  1887,  Jan.  18,  10  days 

Earthquakes. 

6,500. 

S.,  14  m. 

The  intervals  between  these  eruptions,  reckoning  (A)  be- 
tween their  beginnings  and  (B)  between  the  end  of  each  and 
the  beginning  of  the  following  one,  are  :  — 

28 


218  VOLCANIC  ACTION. 


A. 

B 

Between  eruptions  1  and  2 

10 

years  8  months. 

10 

years 

7  months 

2  and  3 

8 

9» 

7 

n 

8 

1 1 

5i-     „ 

3  and  4 

6^ 

15 

6       „ 

4  and  5 

3 

^, 

6 

J5 

3 

5       ,, 

5  and  6 

3 

1 1 

5 

»» 

2 

2       ,, 

6  and  7 

9 

11 

2 

,, 

8 

4       ,, 

7  and  8 

2 

,, 

7 

1> 

12 

7       „ 

8  and  9 

6 

,, 

2i 

5» 

5 

6       „ 

The  eruptions  above  enumerated  —  that  of  1832,  perhaps, 
excepted  —  were  great  eruptions ;  that  is,  they  had  outside 
or  subaerial  outflows.  But  the  history  shows  that  at  other 
times  in  the  sixty-five  years  the  summit  of  the  mountain  has 
been  often  brilliantly  lighted,  and  surmounted  with  a  column 
of  clouds  of  great  height,  made  apparently  from  the  escaping 
vapors,  which  became  a  lofty  column  of  light  at  night.  These 
summit  illuminations  have  been  shown  to  be  evidence  on 
page  197,  not  merely  of  action  in  or  about  the  crater,  but  de- 
cisively of  a  boiling  or  fountain-like  activity  in  the  liquid 
lavas,  if  not  also  of  outflowing  streams.  The  drifting  of 
Pele's  hair  on  such  occasions  thirty-five  miles  to  Hilo  is  as 
good  testimony  to  the  playing  of  jets  or  fountains  as  a  note 
from  an  observer  at  the  summit. 

Moreover,  we  have  learned  from  Kilauea  that  these  times 
of  brilliant  action  within  the  crater  may  be  followed  by 
subterranean  or  submarine  discharges  when  not  by  sub- 
aerial,  and  therefore  that  they  are  not  always  merely 
the  flaring  up  and  fading  out  of  the  crater-fires.  They 
announce  that  the  toj)  of  the  Mount  Loa  cohcmn  of  liquid 
lavas  may  he  up  to  and  in  the  crater,  or  have  its  maximum 
length  and  be  at  serious  work,  even  when  no  outbreak 
ensues. 

The  followino;  table  contains  the  times  of  these  minor  dis- 
plays,  as  well  as  those  of  the  admitted  greater  eruptions.  In 
the  table  the  latter  are  indicated  by  italics. 


PROGRESSIVE  CHANGES  IN  THE  MOUNT  LOA  CRATER.   219 


Dates. 

1.  1832,  June  20. 

2.  1843,  Jan.  9  to  late  in  Feb.,  —  1^  months. 

3.  1849,  May,  2  to  3  weeks. 

4.  1851,  Aug.  8,  —  3  or  4  daj/s. 

5.  1852,  Feb.  15  to  June,  —  about  4  months. 

6.  ,1855,  Aug.  11  to  Nov.,  1856,  — 15  months. 

7.  1859,  Jan.  23  to  Nov.  25,-10  months. 

8.  1865,  Dec.  30,-4  months. 

9.  1868,  March  27  to  April  12 ;    the  flow 

4  daijs. 

10.  1872,  August  10  into  September. 

11.  1873,  Jan.  6,  7,— 2  flays. 

12.  1873,  April  20  to  October,  1874,-18 

months. 

13.  1875,  Aug.  11,  —  one  week. 

14.  1876,  Feb.  13,  —few  days. 

15.  1877,  Feb.  14, —few  clays. 

16.  1880,  May  1. 

17.  1880,  Nov.  5  to  Aug.,  1881,-9  months. 

18.  1887,  Jan.  l<6,—tendaqs. 

19.  1887,  Nov.  25  into  Feb.,  —  one  month. 


Couditions  at  the  Summit. 

Bright  light  at  the  summit,  2-3  weeks. 
Clouds  ;  January  10-17,  bright  light 
Brilliant  light,  just  after  activity  in  Kiiauea. 
Bright  light  for  three  or  four  days. 
Brilliant  light  for  twenty  four  hours. 
Bright  light  at  beginning. 
Brilliant  light  at  first. 
Brilliant  light  for  four  months,  varying  ;  at 

close,  Kiiauea  increases  its  activity. 
Bright  light  from  March  27  to  30. 

Brilliant ;  a  lava-fountain  of  500  feet ;  a  tidal 

wave  on  the  coast ;  Kiiauea  very  active. 
Brilliant. 
Brilliant  more  or  less  for  eighteen  months  ; 

in  June  and  August,  1873,  a  lava-fountain, 

300-600  feet. 
Brilliant. 
Brilliant. 

Brilliant ;  a  submarine  eruption. 
Brilliant;  a  lava-fountain  of  900  feet;  Pele's 

hair  fell  in  Hilo. 
Briglit  for  a  few  days. 
Bright  for  a  few  hours. 
Vapors;  no  liglit  seen. 


The  table  contains  the  dates  of.  ten  periods  of  summit 
activity  or  iilumination  independent  of  the  great  eruptions, 
—  some  short,  but  others  prolonged  for  months,  and  varying 
greatly  in  brightness. 

All  these  minor  displays  have  taken  place  without  initi- 
ating or  announcing  earthquakes. 

It  is  obvious  from  the  tables  that  the  lens^ths  of  the  inter- 
vals  between  the  eruptions  and  the  summit  illuminations  are 
too  various,  so  far  as  now  understood,  to  sustain  the  idea  of 
periodicity. 

Relation  to  Seasons.  —  The  evidence  of  a  seasonal  relation 
appears  to  be  beyond  question.  Out  of  the  whole  number 
(nineteen),  five,  counting  that  of  1865,  occurred  in  January, 
three  in  February,  four  in  March,  April,  and  May,  and  one  in 
June,  —  making  thirteen  in  the  first  six  months  of  the  year. 
Of  the  remainder  four  commenced  in  Auo-ust  and  two  in  No- 
vember.     Thus  fifteen  out  of  the  nineteen  took  place  in  the 


220  VOLCANIC   ACTION. 

wetter  season.  Add  to  these  facts  those  from  Kilauea,  men- 
tioned on  page  125,  where  the  months  given  are  March  (?), 
January  or  June,  May,  Ma}^,  October,  April,  April,  March, 
and  the  number  for  the  same  months  of  the  year  becomes 
twenty  or  twenty-one  out  of  twenty-seven.^ 

Full  meteorological  tables  for  a  comparison  of  the  months 
as  to  precipitation,  both  at  the  base  and  summit  of  the  moun- 
tain, do  not  exist,  and  the  discussion  of  this  important 
question  has  therefore  to  be  left  unfinished. 

The  following  notes  on  the  snows  of  Mount  Loa  are 
from  Mr.  J.  S.  Emerson  of  the  Hawaiian  Government 
Survey  :  — 

"  The  snow-cap  of  Mount  Loa  in  general  may  be  considered  as 
making  its  first  appearance  in  the  early  part  of  November,  and  as 
lasting  until  late  into  March.  This  is  my  impression  from  observa- 
tions the  past  season,  which  I  think  has  not  been  particularly  excepr 
tional.  During  the  early  part  of  November  the  snow-fall  was  quite 
light,  and  seemed  to  melt  rapidly  away  at  its  lower  edges.  By  the 
25th  there  had  been  two  heavy  snow-storms,  covering  the  mountain- 
top  with  a  tliick  coat,  which  lasted  all  through  the  winter.  The  snows 
are  usually  the  heaviest  in  the  month  of  February,  I  think,  though 
I  did  not  see  the  mountain  during  that  month  this  year.  My  last 
view  of  Mount  Loa  was  on  March  29,  when  I  could  just  distinguish 
patches  or  streaks  of  snow  on  the  more  protected  portions  of  the 
summit."  - 

The  relation  to  barometric  changes  is  an  important  subject 
for  future  study,  with  respect  to  which  we  have  now  no 
knowledge.  There  are  also  to  be  investigated  variations  in 
the  amount  of  vapors  over  the  active  craters  dependent  on 
hygrometric  changes. 

In  view  of  the  above  facts  it  is  probable  that  if  there  is 
any  periodicity  in  eruptions  it  is  more  or  less  dependent  on 
meteorological  cycles. 

1  This  relation  to  the  seasons,  first  recognized  by  Mr.  Coan,  is  mentioned  also 
by  Mr.  Green  in  his  "  Vestiges,"  etc.,  p.  332. 
^  Letter  to  the  author. 


PROGRESSIVE  CHANGES  IN  THE  MOUNT  LOA  CRATER.      221 

Variations  in  Activiiy  since  1843.  —  The  copiousness  of 
the  subaerial  discharges  has  diminished  greatly  since  1859. 
Before  the  end  of  that  year,  or  in  the  seventeen  years  from 
1843  to  1860,  five  of  the  eight  great  eruptions  had  occurred ; 
and  of  the  three  in  the  following  twenty-seven  years  only 
one  —  that  of  1880-1881  —  was  of  great  length. 

The  frequent  occurrence  of  the  brilliant  summit  displays 
during  the  twelve  years  preceding  the  middle  of  1880  is 
another  striking  fact.  Six  cases  are  reported ;  and  one  was 
prolonged,  with  small  interruptions,  for  eighteen  months. 

The  first  of  these  displays  occurred  nearly  four  and  a  half 
years  after  the  eruption  of  1868.  But  Mr.  Coan,  the  moun- 
tain chronicler,  was  absent  in  this  country  during  one  year 
ill  the  interval,  —  from  the  spring  of  1870  to  that  of  1871. 
After  the  summit  display  of  August,  1872,  they  came  at 
short  intervals,  their  lengths  from  the  end  of  one  yeai'  to  the 
beginning  of  another,  reckoned  in  months,  being  five,  three, 
ten,  six,  twelve.  After  February  of  1877  there  was  the 
longer  interval  of  three  and  a  third  years.  Such  short-period 
alternations  seem  to  imply  the  recurrence  after  each  of  a  sub- 
terranean discharge  somewhere,  if  not  a  subaerial.  The  dis- 
play of  1877  quite  certainly  ended  in  a  submarine  eruption, 
and  probably  that  of  1872  (pp.  202,  197). 

The  Changes  in  Dejjth  of  the  Summit  Crater.  —  The 
changes  since  the  year  1834,  when  the  crater  was  visited  by 
Douglas,  have  diminished  its  depth  by  at  least  four  hundred 
feet,  if  we  may  trust  —  as  we  probably  ought  to  do  —  his 
measurement  "  with  a  line  and  plummet,"  making  it  1,270 
feet.  In  1840  Lieutenant  Eld,  U.  S.  N.,  of  the  Wilkes 
Exploring  Expedition,  made  the  depth  on  the  west  side 
784  feet  (p.  183),  and  in  1885  J.  M.  Alexander  800  feet 
(Plate  X.). 

We  know  nothing  as  to  variations  in  the  level  of  the  floor 
after  and  before  an  eruption,  and  nothing  as  to  the  down- 
plunges  which  have  followed  discharges.     The  terrace-levels 


222  VOLCANIC   ACTION. 

situated  at  the  north  and  south  ends  of  the  crater  may  mark 
high  lava-levels  just  previous  to  some  ancient  eruption,  but 
they  antedate  history  ;  for  Wilkes's  map  (p.  184)  shows  that 
they  existed  in  1840,  very  much  as  now.  The  map  (Plate  X.) 
by  J.  M.  Alexander,  which  contains  his  ''estimates"  of  the 
dejDths  of  the  terraces  or  ''  plateaus  "  below  the  highest  jDoint 
or  summit,  makes  the  terrace  at  the  south  end  on  a  level 
with  the  upper  of  the  two  at  the  north  end,  suggesting  thus 
that  the  two  may  mark  one  of  the  high  lava-levels  of  the 
crater.  In  addition,  it  places  the  bottom  of  the  South  Crater 
(D),  and  that  of  the  pit  in  the  upper  north  terrace  or  plateau 
(A'),  at  or  below  the  level  of  the  bottom  of  the  central  crater, 
favoring  the  view  that  all  three  parts  of  Mokuaweoweo  are 
still  in  active  connection  ;  which  view  is  sustained  by  the 
facts  (1)  that  the  fountain  of  May,  1880,  was  a  South  Crater 
fountain,  and  (2)  that  the  pit  A'  was  formed  since  1874,  as  it 
is  not  in  Lydgate's  map  of  the  crater  of  that  year. 

2.   The  Ordinary  Work  of  the  Mount  Loa  Crater. 

General  Course  of  Action.  —  Although  but  few  ascents 
to  the  summit  crater  have  been  made  since  the  first  by 
Douglas  in  1834,  and  only  five  of  these  found  the  crater  in 
action,  there  are  still  facts  enough  for  important  conclusions. 
The  cycle  of  changes  has  been,  beyond  doubt,  the  same  essen- 
tially as  in  Kilauea,  —  that  is,  when  a  discharge  takes  place  : 
(1)  the  lava  of  the  lava-column  within  the  central  conduit  of 
the  mountain  falls  to  a  level  some  distance  below  the  crater 
(say  one  or  more  hundred  feet),  as  a  consequence  of  the  loss 
by  the  outflow.  Then  begins  (2)  a  rising  of  the  lava  of  the 
column  until  it  again  shows  part  of  its  fiery  top  in  the  bot- 
tom of  the  crater  engaged  in  its  usual  projectile  work,  and 
until  finally  it  has  reached  a  maximum  height ;  and  then 
follows  (3)  a  new  discharge,  and  another  time  of  inactivity 
for  the  crater. 


ORDINARY   WORK   OF   THE   MOUNT   LOA   CRATER.        223 

The  Projectile  Action  imthin  the  Crater.  —  Projectile  ac- 
tion in  the  Mount  Loa  crater  is  in  strong  contrast  with  that 
of  Kilauea.  Instead  of  the  Kilauea  feature  of  low  jets  sug- 
gesting ordinary  ebullition,  witli  only  occasional  throws  to  a 
height  of  one  to  two  hundred  feet,  the  descriptions  of  the 
summit  action  tell  solely  of  fountains  of  clustered  jets 
seventy-five  to  six  and  even  nine  hundred  feet  high,  as  if 
the  height  of  the  jets  or  the  intensity  of  the  action  were 
proportional  to  the  height  of  the  lava-column.  The  four 
accounts  of  this  activity  —  one  in  1872,  three  in  1873,  and 
one  in  1880  —  are  alike  in  this  respect.  One  of  the  three 
in  1873  describes  the  crater  when  the  summit  light  appeared 
feeble  from  below,  and  the  others  when  brilliant,  and  the 
former  is  scarcely  less  marvellous  in  its  fountains.  The  evi- 
dence is  almost  conclusive  that  such  fountains  are  of  ordinary 
occurrence.  This  was  the  opinion  of  Mr.  Coan ;  and  Mr. 
W.  L.  Green,  in  view  of  his  summit  observations  in  1873 
and  the  reported  facts  of  others,  ascribes  to  all  the  periods 
of  summit  illumination  '"great  fountains." 

3.    Causes  op  the  Ordinary  Movements  within  the  Crater. 

The  Rise  of  the  Lava  in  the  Conduit.  —  The  rise  of  the 
conduit  lava  may  be  safely  attributed  in  part,  probably  a 
large  part,  as  in  Kilauea,  to  the  quietly  acting  ascensive  force 
in  the  lava-column. 

The  other  volcanic  agency  of  greatest  prominence,  as  ad- 
mitted for  other  volcanoes,  is  that  of  the  rising,  expanding, 
and  escaping  vapors.  The  vesiculating  effects  of  the  vapors 
as  regards  the  Mount  Loa  flow  of  1880-1881  have  been 
already  described  on  page  166  ;   and  it  remains  to  consider  — 

77^6  Cause  of  the  High  Projectile  Action  in  the  Summit 
Crater.  —  Higher  projectile  action  in  Mount  Loa  than  in 
Kilauea  through  the  escape  of  elastic  vapors  might  come  (1) 
from  greater  viscidity  in  the  lava,  or  (2)  from  less  specific 


224  VOLCANIC  ACTION. 

gravity  of  the  material,  or  (3)  from  a  larger  supply  of  vapors. 
The.  first  of  these  causes  cannot  be  the  right  one,  for  greater 
viscidity  should  lead  to  high  cinder  ejections  ;  on  the  contrary, 
the  lavas  show  that  they  are  as  mobile  as  the  Kilauea  lavas 
by  the  velocity  of  the  lava-streams  and  all  the  attending  phe- 
nomena, and  more  by  the  free  play  of  the  fountains.  The 
second  is  set  aside  by  the  identity  of  the  lavas  in  density, 
even  to  the  occurrence  of  heavy  chrysolite  lavas  with  a  spe- 
cific gravity  of  3-2. 

If  neither  of  these  explanations  meets  the  case,  we  have 
only  the  third  to  appeal  to,  —  a  greater  volume  of  elastic 
vapors.  It  is,  accordingly,  probable  that  the  cause  which  can 
produce  occasional  jets  of  one  to  two  hundred  feet  in  Kilauea 
is  capable  of  producing  the  jjrevaiUng  high  jets  or  fountains 
of  the  summit  of  Mount  Loa.  The  amount  of  work  done 
there  is  ordinarily  at  least  one  hundred  to  a  thousand  times 
greater  than  in  Kilauea ;  for  the  jets  are  five  to  ten  times 
higher.  But  why  should  the  volume  of  vapors  in  the  lava- 
column  be  greatest  at  the  summit  ? 

This  difference  in  amount  could  not  be  a  fact  if  the  vapors 
within  the  slowly  ascending  lavas  were  from  the  profound 
depths  that  supply  the  lava,  or  even  from  depths  much  below 
the  sea-level.  For,  under  such  circumstances,  (1)  the  differ- 
ence in  the  amounts  carried  up  to  the  two  craters  would  be 
small,  since  the  rate  of  supply  from  below  would  be  essen- 
tially uniform  ;  and  (2)  the  difference  in  the  height  of  the 
columns  would  be  more  favorable  to  Kilauea,  whose  lava- 
column  rises  above  tide-level  but  thirty-seven  hundred  feet, 
than  to  Mount  Loa,  nine  thousand  feet  higher.  The  area  of 
the  floor  of  Kilauea  exceeds  that  of  Mount  Loa. 

But  if  fresh  water  from  precipitation  over  the  island  sup- 
plies the  vapors,  then  the  difference  in  the  heights  of  the 
lava-columns  is  greatly  in  Mount  Loa's  favor.  A  section  of 
its  lava-colurnn  at  the  sea-level  may  receive  moisture  during 
the  whole  time  of  its  rise  to  the  summit,  a  distance  3-8  times 


ORDINARY   WORK   OF   THE   MOUNT   LOA   CRATER.        225 

that  for  Kilauea.  The  ratio  3-8  to  1  for  the  difference  in 
supply  of  moisture  to  the  columns  would  be  too  large  on 
account  of  the  little  precipitation  over  the  upper  part  of  the 
mountain  and  the  much  less  extent  of  surface  in  this  part ; 
but  it  may  safely  be  put  at  2  to  1,  if  not  2i  to  1.  The  ascen- 
sive  movement  in  the  Mount  Loa  lava-column  may  be  some- 
what more  rapid  than  in  the  shorter  conduit  of  Kilauea, 
provided  the  hotter  central  portion  derives  any  upward  thrust 
from  the  pressure  of  the  cooler  lateral  portion,  as  suggested 
on  page  168  ;  and  this  cause  would  diminish  the  difference 
between  the  two  as  to  the  supply  of  vapor  received,  yet  not 
largely. 

The  fact  here  apparently  established  —  that  only  through 
waters  from  the  island-precipitation  could  Mount  Loa  get  its 
larger  supply  —  affords  new  evidence  that  the  inland  ivaters 
are  the  chief  source  of  the  vapors  concerned  in  Hawaiian  vol- 
canic action. 

Is  there  any  other  Source  of  the  Projectile  Actio?i  /  —  The 
lava-fountains  of  the  summit  crater  are  so  marvellous  in  size 
considering  the  density  of  the  lavas,  so  near  the  incredible, 
that  we  naturally  seek  for  other  possible  explanations. 

Hydrostatic  pressure  is  out  of  consideration,  inasmuch  as 
the  fountains  are  at  the  summit  of  the  dome,  and  at  times 
throw  their  jets  fifty  to  a  hundred  feet  above  the  mountain's 
top,  —  over  fourteen  thousand  feet  above  the  sea-level. 

Another  source  of  projectile  action  has  been  suggested  by 
Mr.  Green,  as  briefly  mentioned  on  page  175.  In  opposition  to 
other  writers  on  volcanoes,  he  sets  aside  the  idea  that  vapor 
of  water  is  concerned  effectually  in  the  projectile  action  even 
of  Kilauea.  The  feeble  amount  of  vapors  observed  by  him 
over  the  fountain  of  the  summit  crater  in  1873,  and  the  gen- 
eral absence  of  vapors  from  the  flowing  lava-streams  of  1859 
and  1880-1881,  besides  other  similar  facts,  have  led  him  to 
his  position  on  this  point.     He  recognizes  the  fact  ^  that  great 

1  Vestiges  of  the  Molten  Globe,  pp.  75,  162-167,  175,  272-278,  309,  314. 

29 


226  VOLCANIC   ACTION. 

heaps  and  columns  of  clouds  form  over  an  active  crater,  and 
rise  at  times  to  a  height  of  many  thousands  of  feet ;  but  ac- 
counts for  these  on  the  assumption  that  the  heated  current 
ascending  from  the  active  crater  derives  rapid  accessions  of 
air  from  either  side,  and  this  air,  by  being  carried  up  to  cold 
heights,  yields  the  moisture  by  condensation,  and  so  forms 
the  column  of  clouds.  Further,  he  finds  a  cause  of  some 
projectile  action  for  the  Kilauea  lava-lakes  and  others  in  at- 
mospheric air  carried  down  by  the  descending  lavas  of  the 
jets  into  the  lava-lakes,  —  as  the  crests  of  waves  carry  down 
air  into  the  sea  ;  and  for  the  rest  of  it,  or  that  producing  the 
crater-fountains  like  those  of  Mount  Loa,  he  holds  that  the 
ascensive  action  in  the  conduit,  after  a  time  of  quiet,  sud- 
denly overcomes  resistance  or  stoppages  that  have  come  to 
exist  in  the  conduit  at  depths  below,  and,  as  a  consequence, 
the  lavas,  suddenly  released,  are  thrown  up  in  fountains,  like 
the  jets  of  mineral  oil  from  an  artesian  boring. 

Part  of  the  argument  as  to  the  absence  of  vapors  of  water 
has  already  been  met  in  the  remarks  on  vesiculation,  by 
showing  (1)  how  extremely  little  moisture  is  needed  to  pro- 
duce vesiculation,  and  (2)  how  much  moisture  hot  air  will 
dissolve  and  make  invisible.  It  has  also  been  stated  (3)  that 
if  a  lava-stream,  flowing  down  Mount  Loa,  has  but  a  single 
fountain-head,  as  is  generally  supposed,  though  not  proved, 
nearly  all  the  vesiculation  must  occur  at  the  source,  so  that 
for  this  reason  and  the  heated  air  above  it,  the  lava-stream 
should  be  vaporless,  or  appear  so,  except  where  there  are 
fissures  below  for  additional  supply.^ 

Further  (4),  direct  observation  proves  that  the  vapors  come 
up  out  of  the  crater.  They  often  rise  directly  from  the  orifice 
of  the  crater,  too  low  down  for  the  air-current  to  have  got 
into  action ;  and  in  such  cases  there  is  an  obvious  source  for 

*  Mr.  Green  states,  as  an  exceptional  case,  that  at  one  place  oii  the  Mount  Loa 
flow  of  1880-1881  the  lavas  spread  into  a  large  lake,  and  vapors  rose  from  it  in 
great  amount.  This  is  good  evidence  of  the  existence  there  of  a  local  supply  of 
lavas  through  a  fissure. 


ORDINARY   WORK  OP  THE   MOUNT   LOA   CRATER.        227 

the  condensed  moisture,  and  that  is,  the  liquid  lavas  of  the 
crater.  Mr.  Green  expresses  the  fact  well  in  the  words  :  ^ 
"  There  is  very  often  a  large  quantity  of  smoke  seen  to 
arise  from  the  orifices  of  eruption,  and  this  often  spreads 
out  in  the  higher  regions  of  the  atmosphere.  There  was  a 
column,  perhaps  five  hundred  feet  wide  and  ten  thousand 
high,  arising  from  the  orifice  of  1859  when  we  pitched  our 
tent  alongside  it,"  —  a  point  on  the  mountain  ten  thousand 
five  hundred  feet  above  the  sea-level. 

Further  (5),  the  feeble  amount  of  vapor  observed  by  him 
in  1873  over  the  fountain  in  the  summit  crater,  so  unlike 
what  had  existed  a  few  days  before,  may  have  its  explana- 
tion in  the  dryness  of  the  atmosphere  at  the  time.  The  air 
is  generally  dry  at  the  summit,  but  must  have  its  phases  of 
unusual  dryness,  during  which  an  unusual  amount  of  escap- 
ing moisture  would,  for  this  reason,  l^ecome  invisible. 

(6)  The  summit  fountain  is  a  combination  of  jets,  each  of 
which  must  have  had  its  initiating  projectile  act,  and  it  con- 
tinues for  weeks  and  months  ;  and  this  is  at  variance  with 
the  evidence  from  Kilauea,  which  makes  the  ascensive  action 
very  gradually  and  quietly  lifting,  instead  of  projectile. 

Finally  (7),  the  cold  atmospheric  air  carried  down  into  a 
lava-lake  by  the  jets  could  generate  very  little  projectile 
power.  The  air,  on  entering  the  lavas,  would  encounter  a 
temperature  near  2000°  F.  if  not  beyond  it,  and  hence  the 
expansion  would  cause  expulsion,  or  a  speedy  escape,  in 
spite  of  any  currents  or  intestine  movements  that  might 
exist  in  the  boiling  caldron. 

For  these  reasons  we  may  conclude  that  the  old  and  gen- 
erally accepted  explanation  which  attributes  the  projectile 
action  chiefly  to  water-vapor  is  not  seriously  invalidated  by 
the  ingenious  suggestions  brought  forward  by  Mr.  Green. 


^  Vestiges  oi'  the  Molten  Globe,  p.  169. 


228  ERUPTIONS   OF   MOUNT    LOA   AND   KILAUEA. 

SOLFATARIC     ACTION. 

The  escaping  vapors  produce  incrustations  of  sulphur  at 
the  mouths  of  fissures  in  and  about  the  crater ;  but  owing 
to  the  intermittent  character  of  the  emissions,  years  often 
intervening  between  its  periods  as  between  times  of  erup- 
tions, no  accumulations  of  sulphur  or  of  other  solfataric 
products   exist  about  the   summit. 

•  In  the  caverns  of  lava-streams,  where  the  escape  of  hot 
vapors  is  sometimes  long  continued  when  they  are  sit- 
uated over  fissures,  the  same  incrusting  products  have 
been  observed  as  in  Kilauea,  among  which  glauber  salt 
is  sometimes  abundant,  as  formerly  in  a  cave  near  Kailua. 
Alum  appears  to  be  an  unusual  result  in  these  basaltic 
regions. 


C.     ERUPTIONS   OF   MT.    LOA   AND   KILAUEA. 

In  the  following  pages  the  subjects  considered  are:  (I.)  The 
Characteristics  and  Causes  of  Eruptions  ;  (II.)  Metamorphism 
under  Volcanic  Action  ;  (III.)  The  Form  of  Mount  Loa  as  a 
Result  of  its  Eruptions;  (IV.)  The  Relations  of  Kilauea  to 
Mount  Loa;  (V.)    General  Volcanic  Phenomena. 

Under  the  head  of  Eruptions,  the  principal  topics  are  :  the 
Kinds  ;  the  Places  of  Outbreak  ;  the  Causes  ;  the  Characters 
of  the  Lava-streams ;  the  Position  and  Origin  of  the  subordi- 
nate Lateral  Cones. 

I.    Characteristics   and   Causes   of   Eruptions. 

Eruptions  are  of  two  kinds  :  (1)  Non-explosive  eruptions, 
or  quiet  outflows,  seismically  attended  or  not;  (2)  Exp)losive 
eruptions,  or  catastrophic  upthrows.  There  are  also  combi- 
nations of  the  two  kinds. 


ORDINARY   OR  NON-EXPLOSIVE  ERUPTIONS.  229 


1.     ORDINARY  OR  NON-EXPLOSIVE  ERUPTIONS. 

Kilauea  and  Mount  Loa  are  alike,  as  has  been  shown,  in 
(1)  their  mode  of  work;  (2)  the  southward  position,  in  the 
crater,  of  the  point  of  greatest  activity;  and  (3)  the  general 
features  of  their  eruptions.  But  in  amount  of  eruptive  work 
the  summit  crater  is  far  ahead  of  Kilauea,  and,  in  fact,  it 
leads  the  world.  Kilauea  has  had  but  one  subaerial  outflow 
of  any  magnitude  in  the  last  fifty  years,  and  that  only 
twelve  miles  long.  Mount  Loa,  on  the  contrary,  although 
nearly  thirteen  thousand  feet  up  to  the  bottom  of  the 
crater,  has  had  in  the  same  time  only  one  of  its  eight  less 
than  twelve  miles  long,  and  several  between  twenty  and 
thirty-five ;  and  it  has  reached  its  height  without  a  loss  of 
eruptive  power.  It  is  reasonable,  therefore,  that  Mount  Loa 
should  have  most  instruction  to  give  about  outflows. 

Height   and   Position   op  Outbreaks. 

The  Height.  —  The  place  of  outbreak  of  a  Mount  Loa 
eruption  may  have  any  height  from  the  summit  to  levels 
far  below  the  sea-level ;  and  this  ''far  below  "  may  be  (as  the 
map  on  page  26  shows)  17,250  feet  down,  before  reaching 
the  actual  foot  of  the  eastern  slope.  The  heights  of  known 
occurrence  are  mentioned  in  the  table  on  page  217.  The 
completion  of  the  topographical  survey  of  Hawaii,  now  in 
progress  under  the  Government,  will  before  long  give  more 
correct  figures.  The  height  of  the  source  of  the  one  Ki- 
lauea outflow,  that  of  1<S40,  or  rather  of  the  spot  where  it 
appears  to  have  begun,  is,  according  to  Wilkes,  1,244  feet 
above  tide-level. 

In  each  of  the  cases  of  eruption,  fractures  were  made  near 
the  summit  which  extended  down  the  mountain  to  the  place 
of  chief  outflow,  with  only  small  discharges  along  them,  when 
any.      In  some'  cases  fissures  have  opened  on  the  brink  of 


230  ERUPTIONS   OF   MOUNT   LOA   AND   KILAUEA. 

the  crater  and  let  out  lavas ;  but  all  the  large  outflows  of 
modern  time  have  come  from  points  a  thousand  feet  or 
more  below  the  summit. 

Relations  between  the  Positions  of  the  Places  of  Outbreak 
and  the  Diameter's  of  the  Craters.  —  The  course  of  the  northern 
half  of  the  longer  diameter  of  the  summit  crater  is  about 
N.  35°  E.,  and  that  of  the  southern  half  about  N.  20°  E.  or 
S.  20°  W.,  as  marked  on  the  upper  and  lower  margin  of  Plate 
X.  Four  of  the  largest  lava-streams  of  Mount  Loa  —  those 
of  1843,  1852, 1855,  and  1880  — and  two  others  to  the  south 

—  those  of  1868  and  1887 — have  their  places  of  outbreak 
nearly  in  the  line  of  the  respective  halves  of  the  longer  diameter. 
Again,  three  of  the  eruptions  —  those  of  1851,  1859,  and  1877 

—  broke  out  on  the  west  side  of  the  summit,  nearly  in  the  line 
of  the  shorter  diameter,  or  between  the  summit  and  Hualalai. 

There  is  here  probable  evidence  of  a  dependence  of  the 
eruptions  to  some  extent  on  the  two  great  fissure-lines  upon 
or  about  which  the  mountain's  foundations  were  laid. 

In  Kilauea  the  direction  of  the  longer  diameter  is  about 
N.  50°  E.  -  S.  50°  W.  The  chief  course  of  eruptions,  as  on 
Mount  Loa,  is  marked  by  a  line  of  fissures  and  ejections 
running  west-southwestward  in  the  direction  of  the  longer 
diameter.  But  the  large  outflow  of  1840,  and  the  fissures 
leading  to  it,  instead  of  pointing  away  from  the  crater,  have 
a  course  nearl}^  parallel  to  the  longer  diameter,  but  fifteen 
miles  south  of  the  Kilauea  line.  This  is  seen  on  the  map 
(Plate  I.),  the  stream  being  the  one  near  the  east  cape. 

Causes   of   Eruptions. 

State  of  Peadiness  for  an  Eruption.  —  The  ordinary  quiet 
work  of  the  craters  has  been  shown  to  be  carried  on  by  — 

(1)  The  ascensive  force  of  the  conduit  lavas  :  producing 
(a)  a  slow  rise  in  the  liquid  rock  from  depths  below  ;  and 
(h)   a  raising  of  the  crater's  bottom. 


ORDINARY   OR  NON-EXPLOSIVE   ERUPTIONS.  231 

(2)  The  elastic  force  of  rising,  expanding,  and  escaping 
vapors :  producing  jets  and  fountains  in  the  lava-lakes ; 
overflows  or  ejections  spreading  the  lavas  over  the  crater's 
bottom  ;  vesiculation  of  the  lava,  and  consequent  increase 
of  its  bulk. 

Other  causes  have  been  mentioned  as  occasionally  in  action 
on  page  169,  but  as  not  essential  to  the  chief  results. 

After  a  season  of  this  ordinary  activity,  with  more  or  less 
gradual  increase  of  intensity,  a  state  of  readiness  for  an 
eruption  and  its  determining  conditions  have  been  reached. 
This  has  happened  when  the  lava  has  risen,  through  these 
agencies,  to  what  might  be  called  high-lava  mark  ;  a  level 
some  hundreds  of  feet  above  low-lava  mark  or  the  low  level 
occasioned  by  the  preceding  discharge. 

Action  needed  for  an  Eruption.  —  After  this  preparation 
nothing  is  needed  for  an  eruption  but  an  agency  of  sufficient 
force  to  break  the  lava-conduit ;  for  if  broken  seriously  the 
lava  will  run  out,  and  therein  is  an  eruption  or  discharge. 

Neither  of  the  agencies  carrying  on  the  ordinary  quiet 
work  of  the  volcano  has  shown  itself  capable,  during  historic 
time,  —  that  is,  since  1822,  —  of  breaking  the  lava-conduit 
for  a  discharge.  The  escaping  vapors  have  spent  their  force 
mostly  in  making  jets  and  fountains  and  feeble  outflows 
within  the  crater ;  and  still  more  quiet  has  been  the  work 
of  the  ascensive  force.  Eruptions  have  been  a  sequel  to 
years  of  this  quiet  work,  but  not  a  direct  effect  of  the  action. 

Agency  of  Earthquakes.  —  Earthquakes  have  often  been 
considered  an  effective  agent  in  eruptions.  But  during  the 
past  sixty-seven  years  only  two  of  the  eruptions  of  Mount  Loa 
and  one  of  Kilauea  have  been  introduced,  or  attended,  by  no- 
ticeable earthquakes.  The  eruptive  agent  in  both  volcanoes 
has  in  general  worked  quietly,  —  "  as  quietly  as  the  moon 
rises,"  says  one  writer  without  much  exaggeration.  The  star- 
like light  on  Mount  Loa  has  been  followed  soon  by  a  stronger 
glow  ;  and,  accompanying  this,  a  rising  of  clouds  into  heaps 


232  ERUPTIONS   OF   MOUNT   LOA   AND   KILAUEA. 

and  lofty  columns.  After  a  day,  or  two,  or  three,  the  sum- 
mit light  having  disappeared,  the  flow  has  begun  one,  two,  or 
three  thousand  feet  below  the  top  ;  and  a  line  of  light  has 
then  slowly  lengthened  down  the  mountain  for  twenty  or 
thirty  miles ;  and  all  this  quietly.  It  is  the  grandest  of 
volcanic  work  with  the  least  possible  display  of  force. 

The  facts  connected  with  the  two  eruptions  of  Mount  Loa 
and  one  of  Kilauea,  that  were  attended  by  earthquakes,  merit 
special  review  in  this  place  because  they  teach  what  earth- 
quakes may  do,  and  by  what  means.  The  three  occurred  in 
the  years  1868  and  1887. 

On  a  Friday  in  1868,  March  27,  as  stated  on  pages  89,  194, 
a  light  was  seen  on  the  mountain,  and  feeble  earthshocks  oc- 
curred. Only  slight  eruptions  followed.  Then,  in  accordance 
with  the  ordinary  rule,  these  first  fires  at  the  summit  dis- 
appeared. But  the  earthquakes  increased  in  violence,  —  not 
about  the  summit,  but  far  to  the  southwestward,  within  the 
lower  three  or  four  thousand  feet  of  the  mountain.  And 
they  continued  increasing  until  that  "  terrible  shock "  of 
Thursday,  April  2.  Five  days  later,  April  7,  the  lava  burst 
out  from  an  opened  fissure  at  a  point  twenty-three  miles  distant 
from  the  summit,  and  only  ten  or  eleven  from  the  sea-coast. 
The  reader  should  refer  to  the  map  (Plate  I.),  where  the  posi- 
tion of  the  outflow  is  given. 

It  is  here  manifest  that  the  earthquakes  had  nothing  to  do 
with  pi^eparing  for  the  eruption ;  they  were  too  late  for  this. 
It  is  possible  that  the  first  break  near  the  summit  anticipated 
the  first  earthshock.  But  below,  in  the  region  of  most  vio- 
lent disturbance,  greater  fissures  were  opened,  the  profoundest 
probably  at  the  very  time  of  that  "  terrible  shock  ; "  and  as 
soon  after  as  the  subterranean  passage  could  be  made  —  about 
five  days — the  lava  from  the  broken  lava-conduit  or  reservoir 
made  its  appearance  at  the  surface  and  hurried  down  the 
mountain  to  the  sea.  But  at  the  sea-border  and  elsewhere 
the  fissures  were  probably  ahead   of  the  lava,  according  to 


ORDINARY   OR  NON-EXPLOSIVE   ERUPTIONS.  233 

Prof.  C.  H.  Hitchcock,  and  gave  it  exit  nearly  all  the  way, 
occasioning  their  rapid  progress  seaward. 

Here,  then,  it  is  clear  what  the  earthquakes  did  to  produce 
the  eruption.  They,  or  the  cause  generating  them,  broke  a 
hole  into  the  conduit,  and  the  lava  escaped.  The  lava  of  the 
conduit  was  not  thrown  into  commotion  or  projected  to  great 
altitudes  at  the  suniin/t :  instead  of  this  it  sank  out  of  sisfht, 
following  the  rent  to  the  surface  far  down  the  mountain. 

These  events  were  repeated  almost  precisely  in  the  Mount 
Loa  eruption  of  1887.  The  locus  of  the  outflow  and  of  the 
earthquakes  in  both  cases  was  far  south  in  southern  Hawaii, 
and  the  two  streams  followed  near  and  parallel  lines.  The 
chief  difference  between  them  was  in  the  higher  outlet  in 
1887  by  twenty-five  hundred  or  three  thousand  feet. 

The  1868  earthquake  eruptions  of  Kilauea  and  Mount  Loa 
were  coincident  in  time.  The  earthquakes  were  the  same 
identical  earthquakes  ;  and  that  ^'  terrible  shock  "  of  April  2 
was  for  each  the  special  discharging-agent.  Immediately 
after  the  shock,  the  fires  of  Kilauea,  before  unusually  active,^ 
commenced  to  decline  ;  by  night  of  that  Thursday  all  the 
burning  cones,  by  night  of  Saturday  all  the  smaller  lava- 
lakes,  and  by  Sunday  night  the  great  South  Lake  had  become 
extinct.  And  then,  the  lavas  having  run  off.  half  the  floor 
of  the  great  crater  of  Kilauea  sank  down  three  hundred  feet. 

A  genetic  connection  between  the  earthquake  disturbance 
and  the  eruption  cannot  be  doubted.  The  earthqi^akes  came 
after  the  crater  had  reached  a  state  of  unusual  activity,  and 
hence  could  have  taken  no  part  in  the  preparation.  They 
simply  discharged  the  lava  by  breaking  the  conduit  that 
held  it. 

*  Dr.  W.  Hillebrand  states  that  for  two  months  previous  to  the  eruption  there 
were  eight  lava-lakes  in  the  bottom  of  Kilauea  ;  and  until  March  17,  a  very  active 
blow-hole  in  the  northwest  corner,  where  "  large  masses  of  vapor  were  thrown  off  as 
from  a  steam-engine."  On  Thursday,  April  2,  after  the  earthquake,  there  were  fear- 
ful detonations  in  the  crater,  and  portions  of  the  wall  tumbled  in  ;  and  then  began 
the  decline. 

30 


234  ERUPTIONS   OF   MOUNT   LOA   AND   KILAUEA. 

Moreover,  the  earthquakes  which  thus  emptied  Kilauea 
were  of  Mount  Loa  origin ;  they  had  their  centre  thirty  miles 
or  more  west  of  Kilauea,  and  were  made  through  the  Mount 
Loa  fires.  It  is  a  case,  therefore,  of  one  mountain-volcano 
accidentally  discharging  the  conduit-lava  of  another.  The 
work  was  simply  a  fracturing  of  the  mountain  in  different 
directions,  —  for  the  island  was  violently  shaken  from  the 
west  side  to  Hilo,  on  the  east  coast ;  and  in  the  general  frac- 
turing the  two  volcanic  conduits  were  broken  at  once,  an 
accident  not  likely  to  happen  often. 

It  is  also  to  be  noted  that  the  earthquakes  ivere  of  local  or 
volcanic  origin.  This  is  established  by  the  fact  that  only  two 
of  the  heaviest  shocks  reached  westward  to  Honolulu  on 
Oahu  (p.  195) ;  and  these  so  feebly  that  they  did  not  make 
themselves  generally  felt  in  that  city.  The  depth  of  the 
oceanic  depression  between  Hawaii  and  Oahu,  which  is  only 
five  hundred  fathoms  where  least  (between  Hawaii  and  Maui, 
map,  p.  26),  was  sufficient  to  stop  off  the  vibrations. 

Further,  as  in  the  Mount  Loa  eruptions,  no  increase  of  pro- 
jectile action  was  occasioned  in  the  crater  of  Kilauea  by  the 
earthquake  disturbance  ;  the  lavas  simply,  in  the  quietest 
way,  ran  off,  leaving  the  crater  empty,  still,  and  dark. 

A  mountain  having  within  it  two  great  regions  of  liquid 
lava  thousands  of  feet  in  height,  ten  thousand  feet  or  more 
in  diameter,  and  each  at  a  temperature  above  2000°  F.,  and 
with  subterranean  waters  abundant,  at  least  through  the 
lower  two-thirds  of  the  altitude,  is  well  fitted  for  the  produc- 
tion of  eruptive  crises.  It  is  remarkable  that  the  eruptions 
of  1868  and  1887  are  the  only  ones  seismically  occasioned,  or 
attended,  in  the  past  sixty-five  years  ;  and,  further,  that  in 
these  eruptions,  although  among  the  most  violent  on  record, 
the  craters  were  wholly  free  from  explosive  action. 

The  violent  earthquakes  of  1868  and  1887  accomplished 
nothing  so  far  as  the  eruptions  were  concerned  that  is  not 
effected  on  Hawaii  in  four  eruptions  out  of  five  without  them. 


ORDINARY   OR   NON-EXPLOSIVE   ERUPTIONS.  235 

The  greatest  of  the  eruptions  have  had  no  such  aid.  In  the 
preparation  for  a  discharge,  the  mountain  has  reached  a 
critical  state,  because  of  the  elongation  upward  of  the  fire 
column  ;  it  is  then  that  the  fracturing  agency  does  its  work  ; 
earthquakes  are  only  a  possible  incident.  With  or  without 
them,  the  conditions  and  results  are  the  same  ;  for  vibrations 
necessarily  attend  fracturing,  and  earthquakes  are  simply  the 
stronger  or  perceptible  earthshocks. 

The  Rui^ticring  and  Ejecting  Forces.  —  The  chief  cause  of 
the  rupturing  is  no  doubt  the  elastic  force  of  suddenly  gen- 
erated vapor.  So  far  this  is  an  accepted  explanation.  As  to 
the  conditions  under  which  this  vapor  is  generated,  there  is 
not  so  general  ao;reement. 

The  facts  shov/,  first,  that  on  Hawaii  the  vapors  are  not 
suddenly  generated  'within  the  conduit ;  for,  in  the  event, 
the  lavas  slink  away  from  the  crater,  instead  of  dashing  up 
wildly  to  great  heights.  If  not  generated  loithin,  it  must  be 
ivithout,  and  the  most  probable  region  is  that  of  the  hot  ex- 
terior of  the  conduit,  or  the  hot  rocks  encasing  the  liquid 
column,  or  else  fissures  or  local  fire-places  adjoining  it.  In 
this  view  the  fracturing  depends  on  the  sudden  access  of  sub- 
terranean waters  to  this  outside  region  of  great  heat. 

Secondly,  the  evidence  proves  that  the  force  makes  a  fissure 
or  fissures  for  the  discharge  of  the  lava  without  giving  the 
waters  entrance  into  the  conduit.  The  pressure  of  the  elastic 
vapor  expends  itself  hi  breaking  the  sides  of  the  mountain, 
and  only  under  the  most  extraordinary  circumstances  is 
the  water  forced  into  the  lava-column.  The  earthquakes 
of  1868  were  an  exhibition  of  the  power  generated  ;  and 
hardly  less  so  is  the  noiseless  fracturing  for  the  greatest  of 
eruptions. 

Some  erupting  action  comes  from  hydrostatic  pressure. 
But  the  fact  that  the  fissures  first  open  quite  near  the  sum- 
mit of  Mount  Loa  is  evidence  that  pressure  from  this  source 
is  the  least  efficient  agent. 


236  ERUPTIONS   OF   MOUNT   LOA   AND   KILAUEA. 

Whi  southwestern  Hawaii  should  he  esjitecially  liable  to  vio- 
lent ear'thshocks  in  connection  with  its  outflows  is  not  wholly 
clear.  But  there  are  three  significant  facts  bearing  on  the 
question  :  — 

(1)  The  southern  half  of  the  longer  diameter  of  the  Mount 
Loa  crater,  and  fissures  from  it  down  the  mountain,  point 
directly  to  the  places  of  outbreak  of  1868  and  1887,  the  prob- 
able localities  of  the  earthquake  epicentra  of  those  years. 

(2)  The  longer  diameter  of  Kilauea,  with  a  long  lino  of 
fissures,  having  the  trend  S.  52°  W.,  points  nearly  to  the 
same  region  of  outbreak  ;  so  that  the  tivo  diametral  lines,  the 
Mount  Loa  and  the  Kilauea,  there  intersect.    (See  map,  Plate  I.) 

(3)  These  lines  have  long  been  common  directions  of  frac- 
tures and  eruptions,  as  shown  by  the  old  lavas  of  the  surface 
as  v/ell  as  by  existing  lines  of  fractures.^ 

In  eruptions  the  ejecting  force  may  be  feeble  or  null ;  for 
the  lava  may  flow  out,  when  the  source  favors  it,  simply 
through  gravity  :  but,  in  general,  ejection  is  pushed  forward, 
by  the  elastic  vapors  within  the  lava-column;  by  vapors 
generated  outside,  like  those  producing  eruptions  ;  and  by 
hydrostatic  pressure. 

The  first  of  these  causes  is  the  source  of  the  high  fountains 
in  the  summit  crater  ;  and  the  summit  effects  indicate  that  it 
should  have  great  propelling  power  at  places  of  outflow.  The 
fountains  at  the  outflows  have  hitherto  been  attributed  to 
hydrostatic  pressure  ;  but  the  two  causes  must  here  act  to- 
gether, and  it  is  impossible  to  say  from  present  knowledge 
which  preponderates. 

Fountains  attended  the  outbreak  at  the  eruptions  of  1852, 
1859,  1868,  and  1887  ;  and  it  is  probable  that  examination 
at  other  times  would  have  added  one  or  two  to  the  list.  The 
lengths  of  the  lava-column  (A)  above  the  place  of  outbreak  at 

1  This  divergence  between  the  courses  of  the  longer  diameters  of  the  craters  of 
Mount  Loa  and  Kilauea  comes  up  again  for  consideration  in  the  remarks  on  the 
relations  of  the  two  volcanoes. 


ORDINARY   OR  NON-EXPLOSIVE  ERUPTIONS.  237 

these  eruptions,  and  (B)  the  reported  heights  of  the  fountains 
in  feet,  are  as  follows :  — 


1852 

1859 

1868 

1887 

A 

2500 

3000 

10,000 

7000 

B 

200-700 

300-400 

200;  600? 

80;  200? 

Owino;  to  the  heig-ht  of  the  column  above  the  level  of  the 
outlet  in  1868,  ten  thousand  feet,  the  hydrostatic  pressure 
should  then  have  been  greatest ;  the  force  from  the  vapors  in 
the  lava-column,  least;  and  the  friction  in  the  very  long  pas- 
sage-way from  the  broken  conduit,  the  most  obstructing. 

The  second  source  of  ejecting  and  fracturing  pressure  men- 
tioned above  is  the  probable  origin  of  the  fractures  which 
sometimes  cut  through  the  walls  of  a  crater  to  the  summit ; 
and  if  the  vapors  producing  the  pressure  are  generated  over 
a  source  of  liquid  lava,  the  fissures  would  necessarily  become 
injected  with  lava  which  might  flow  out  above,  in  a  contin- 
uous stream,  down  the  mountain.  Cases  of  'this  kind  about 
Kilauea  occurred  at  the  erujDtions  of  1832  and  1868,  as  men- 
tioned on  pages  56,  90 ;  and  Mr.  W.  T.  Brigham  and  Rev. 
J.  M.  Alexander  mention  others,  of  uncertain  date,  about  the 
summit  crater. 

Mr.  Alexander  speaks  of  a  "  cataract  of  lava  "  descending 
the  walls  into  the  crater  from  the  summit ;  and  farther  south, 
of  two  other  similar  cataracts  ;  and  at  the  summit  he  found 
the  deep  fissure  from  which  the  cataracts  had  been  supplied 
with  lava,  and  ascertained  that  it  had  also  poured  out  an  im- 
mense stream  northward  upon  the  first  plateau,  and  thence 
southward  into  the  central  crater.  "•  On  the  southwest  side  of 
the  crater  there  had  been  another  eruption  from  fissures  that 
were  still  smoking,  and  the  eruption  had  sent  a  great  stream 
southward  toward  Kahuku,  and  had  also  poured  cataracts 
into  the  south  crater  from  all  sides."  "  The  flows  were  from 
some  of  the  highest  parts  of  the  brim  ; ''  and  "  from  the  brink 
there  had  been  large  flows  down  the  mountain."  "  These 
outbreaks  from  fissures  around  the  rim  indicate  that  the  lava 


238  ERUPTIONS   OF   MOUNT   LOA   AND   KILAUEA. 

had  rather  poured  into  the  crater  than  out  of  it ;  and  also 
that  it  had  flowed  from  such  fissures  in  vast  streams  down 
the  mountain  side."  These  cases,  perhaps,  date  from  the 
eruption  of  1880,  the  last  that  preceded  Mr.  Alexander's 
investigation  of  the  crater. 

Such  events,  if  attending  an  eruption,  belong  to  its  very 
beginning,  before  the  lava  is  drawn  oft"  from  the  crater.  They 
may  occur  at  other  times  ;  that  they  do  so  is  not  yet  certain, 
except  in  a  small  way  within  Kilauea,  about  the  lava-lakes. 

Outflows   and   the   Attending   Circumstances. 

Tlie  Source.  —  An  outflow  of  lava  may  commence  as  a 
stream  or  as  a  fountain.  In  either  case  the  pent-up  vapors 
of  the  lava-column  make  their  forcible  escape  with  the  lava  ; 
and  a  cone  of  solidified  lava  more  or  less  scoriaceous  is 
usually  formed  about  the  vent  by  the  pericentric  action. 
These  cones  are  mentioned  in  the  descriptions  of  all  the  out- 
breaks, not  excepting  that  of  1880,  which  was  visited  by 
Rev.  E.  P.  Baker.  Large  deposits  of  cinders,  or  a  light 
scoria,  are  sometimes  distriljuted  over  the  adjoining  region, 
and  Pele's  hair  is  also  a  common  product ;  the  former  where 
the  lava  is  thrown  up  in  fountains  and  partially  cools  ex- 
teriorly as  it  falls  (p.  187),  and  the  latter  from  the  action  of 
either  the  fountains  or  the  low  jets. 

The  summit  crater  of  Mount  Loa,  unlike  Kilauea,  is  often 
left,  after  an  eruption,  with  one  or  more  cinder-cones  on  the 
bottom,  the  larger  of  them  usually  in  the  southern  portion 
of  the  crater.  They  are  probably  made  as  the  heat  declines 
with  the  commencing  retreat  of  the  lavas. 

Bate  of  Flow.  —  The  great  flow  of  1852,  so  grand  in  the 
fountains  at  its  source  and  twenty  miles  long,  was  finished 
in  twenty  days  ;  this  gives  for  its  mean  rate  of  progress  a 
mile  a  day.  The  flow  of  1859,  thirty-three  miles  long,  occu- 
pied only  eight   days,  which  corresponds   to  a  rate  of   four 


ORDINARY   OR   NON-EXPLOSIVE   ERUPTIONS.  239 

miles  a  day  on  a  mean  slope  of  one  foot  in  fifteen.  The 
thirty  miles  to  Hilo  in  the  stream  of  1880-1881  took  nine 
months ;  and  the  mean  slope  was  one  foot  in  thirteen,  or 
abont  five  degrees. 

The  general  conditions  in  the  flow  of  a  great  stream,  its 
obstructions  and  modes  of  overcoming  them,  are  well  de- 
scribed by  Mr.  Coan  on  page  189.  As  to  actual  rate  of  flow, 
we  want  more  precise  facts.  It  is  difficult  to  reconcile  the 
facts  stated  on  these  points,  and  especially  the  various  ve- 
locities attributed  to  the  different  portions  of  a  flowing 
stream ;  for  example,  the  reported  rate  in  one  of  the  tun- 
nels of  ^"  forty  miles  an  hour,"  with  a  rate  for  the  front  of 
the  flow  of  ''  one  mile  a  week."  The  difficulty  is  still  great 
if  we  suppose  the  forty  to  be  only  ten,  whatever  the  obstruc- 
tions along  the  front.  The  conditions  are  those  of  a  dis- 
charging faucet,  and  the  flow  below  is  that  of  the  liquid 
after  its  escape  spreading  widely  over  a  rough  surface. 

The  many  openings  through  the  crust  of  a  stream  into  the 
tunnels,  which  give  out  vapors  and  often  have  the  shape  of 
jagged  cones,  suggest  the  possibility  that  a  fissure  may  exist 
beneath  in  these  and  similar  places  for  the  discharge  of  lava 
and  vapors.  But  the  idea  that  such  fissures  generally  un- 
derlie a  lava-stream  (which  I  formerly  thought  probable)  is 
opposed  by  Mr.  Coan  ;  and  there  are  not  facts  to  sustain  it 
except  for  the  Mount  Loa  stream  of  1868  and  the  Kilauea 
of   1840. 

The  tunnels  of  a  stream,  made  by  a  crusting  of  the  sur- 
face while  the  lava  continues  flowing  beneath,  have  a  smooth, 
and  in  part  a  somewhat  glassy  or  enamelled  interior,  with 
horizontal  flutings  and  mouldings,  which  were  made  by  the 
moving  lava,  as  described  on  page  209.  The  small  capacity 
of  the  tunnel  entered  near  Hilo  suggested  the  following 
queries  :  How  much  of  the  lava  of  a  stream  a  mile  wide 
runs  in  tunnels  ?  Does  the  little  width  of  the  tunnel,  and 
thereby  of  the  supply  stream,  account  for  the  difference  of 


240  ERUPTIONS   OF   MOUNT   LOA   AND   KILAUEA. 

velocity  in  the  tunnels  and  at  the  front  ?  If  so,  the  exit 
should  be  as  free  as  that  from  a  faucet,  or  the  arrangements 
would  not  work.  How  many  such  tunnels  exist  side  by  side  ? 
Does  a  single  tunnel  continue  on  for  twenty  or  thirty  miles 
as  an  uninterrupted  lava-duct  ?  We  should  infer  that  for  a 
large  stream  the  system  of  tunnels  would  become  a  very 
complicated  one. 

Whatever  doubts  exist  as  to  the  rate  of  flow,  there  is  none 
as  to  the  extreme  liquidity  of  the  Mount  Loa  lava,  and  its 
equalling  if  not  exceeding  that    of  Kilauea. 

llie  Amount  of  Lava  DiscJiarged.  —  There  are  no  data  as 
regards  the  breadth  or  the  depth  of  the  streams,  for  a  satis- 
factory calculation  of  the  amount  discharged.  The  depths 
might  at  many  points  be  ascertained  from  the  holes  left 
by  burned  trunks  of  trees.  We  have  two  such  observations 
from  Mr.  Baker  for  the  stream  of  1880-1881,  but  not  enough 
for  an  estimate  of  the  mean  thickness.  We  can  now  only 
make  a  supposition. 

The  flow  of  1852  was  twenty  miles  long.  If  we  suppose 
the  mean  depth  of  the  stream  to  be  twenty  feet,  and  the 
mean  width  5,000  feet,  the  amount  of  lava  it  contains  would 
be  10,560,000,000  cubic  feet.  Supposing  the  lava-column  to 
have  the  mean  diameter  of  the  central  part  of  the  summit 
crater,  9,000  feet,  it  would  contain,  down  to  a  depth  of 
2,500  feet  (the  place  of  discharge  for  that  eruption),  nearly 
160,000,000,000  cubic  feet  of  lava,  or  fifteen  times  as  much 
as  was  discharged.  Accordingly,  the  discharge,  if  the  above 
figures  represent  the  whole  amount,  would  have  drawn  off 
less  than  two  hundred  feet  in  depth  from  the  lava-conduit ; 
and  a  rise  of  two  hundred  feet  again  would  have  made  the 
mountain  ready  for  another  discharge.  The  calculation  is 
suggestive,  tliough  otherwise  of  little  value.  In  addition 
to  the  other  uncertainties  we  know  nothing  as  to  how 
much  of  a  discharge  passes  oft:  into  subterranean  cavities. 
The  amount  may  be  very  large,  for  the  great  eruption  of 


ORDINARY   OR   NON-EXPLOSIVE   ERUPTIONS. 


241 


Kilauea  in  1832  has  little  to  show  over  the  surface  of  the 
island. 

Whatever  the  amount  of  lava,  or  of  height,  that  is  lost  by 
the  lava-column  at  an  eruption,  it  has  taken,  as  has  been 
shown,  but  a  very  short  time,  in  several  cases,  to  fill  up  again 
for  a  new  discharge.  I  repeat  here  that  after  the  eruption 
of  1852,  which  produced  a  stream  twenty  miles  long,  had 
closed,  the  lofty  volcano  was  ready  in  only  three  and  a  half 
years  for  a  twenty-six-mile  flow,  that  of  1855 ;  and  in  three 
and  a  half  years  more,  for  another  still  longer,  that  of,  1859, 
thirty-three  miles  in  length  of  stream,  —  which  is  brisk  work 
•  for  the  great  old  mountain.  According  to  these  facts  the 
lava-column  had  risen,  after  the  eruptions,  at  the  rate  of  at 
least  one  hundred  feet  a  year,  so  as  to  reach  again  the  bot- 
tom of  the  crater  and  be  ready  for  another  discharge. 

Kinds  of  Lava-streams  :  Palioehoe  and  Aa.  —  The  ordi- 
nary smooth-surfaced  lava-stveam,  the  pahoehoe,  needs  here 
no  further  description.  The  aa-stream  is  less  often  seen  in 
process  of  formation,  and  is  more  difficult  to  understand.  With 
reference  to  an  explanation  of  its  origin,  I  repeat  here  from 
page   9   the  characteristics  of  the  typical  kind   (not  of    the 


Portion  of  an  Aa  Lava-stream. 

thinner  streams  that  approximate  to  the  pahoehoe),  and  repro- 
duce also  the  sketch  of  a  portion  of  one  to  aid  the  conception 
of  its  roughness ;  the  reader's  conception  of  it  will  be  feeble 
at  the  best  if  he  has  not  already  had  a  view  of  cliaos. 

31 


242  ERUPTIONS   OF   MOUNT   LOA  AND   KILAUEA. 

a.  The  characters  of  the  cooled  aa-stream :  (1)  a  mass  of 
roiio;h  blocks  one  foot  and  less  to  one  thousand  cubic  feet  in 
size,  loosely  piled  together  to  a  height  of  twenty  to  forty  feet 
above  the  general  level ;  (2)  the  blocks  bristling  with  points, 
but  not  scoriaceous,  and  less  vesiculate  than  most  of  the 
pahoehoe  ;  (3)  the  material  rather  brittle,  and  consequently, 
when  made  up  of  small  blocks  or  pieces,  easily  broken  down 
to  a  flat  surface  by  the  natives  for  the  site  of  a  house;  (4) 
often  aa  making  part  of  a  stream  when  the  rest  is  pahoehoe, 
either  of  the  two  the  chief  part ;  (5)  sometimes  making  one 
stream  from  a  source,  when  another  from  the  same  source 
going  off  in  a  different  direction  is  pahoehoe. 

h.  The  constitution  and  condition  of  the  «a-stream  when 
in  motion :  (1)  a  mass  of  rough  blocks  outside,  precisely  like 
the  cooled  rta-stream  ;  (2)  the  motion  extremely  slow,  indi- 
cating a  semi-fluid  condition  beneath  ;  (3)  a  red  heat  often  in 
front  among  the  blocks;  (4)  fused  rock  seldom  exuding  ;  (5) 
the  blocks  of* the  upper  part  of  the  front,  as  the  stream  creeps 
on,  tumbling  down  the  high  slope,  owing  to  retardation  at 
bottom  from  friction,  and  thus  a  rolling  action  in  the  front 
part. 

The  aa  field,  owing  to  its  crevices  and  shaded  recesses,  re- 
tains moisture,  and  decomposition  at  surface  early  commences, 
which  favors  germination  of  seeds  ;  and  as  I  am  informed  by 
Mr.  Baker,  the  stream  often  becomes  forest-covered  when  the 
pahoehoe  alongside  remains  bare. 

One  of  the  best  published  descriptions  of  an  aa  flow  is  that 
of  Judge  Hitchcock  (p.  206),  which  says  :  "Along  the  whole 
line  of  the  advance  the  stream,  twelve  to  thirty-five  feet  in 
height,  was  one  crash  of  rolling,  sliding,  tumbling,  red-hot 
rock,  no  liquid  rock  being  in  sight ;  with  no  explosions,  but  a 
tremendous  roaring,  like  ten  thousand  blast-furnaces  all  at 
work  at  once."  Mr.  Baker  writes  (letter  of  February,  1888) : 
"  I  have  stood  by  a  wholly  molten  stream  of  lava  which  miles 
below  was  cooling  into  aa" 


ORDINARY   OR   NON-EXPLOSIVE  ERUPTIONS.  243 

Under  the  restrictions  of  such  facts  the  cm  cannot  be  ex- 
plained by  referring  it  to  simply  a  partial  cooling  of  a  stream 
and  then  a  breaking  up  of  the  crust  on  a  new  accession  of 
flowing  lava,  —  a  common  explanation  ;  for  there  is  no  evi- 
dence of  a  crust  from  surface-cooling  analogous  to  that  of 
pahoehoe.  It  is  not  dependent  on  the  mineral  constitution 
of  the  lava,  for  one  and  the  same  stream  may  take  either 
condition ;  and  adjoining  fields  near  Punaluu,  as  the  author 
observed  in  1840  as  well  as  in  1887,  are  at  opposite  extremes 
as  to  the  amount  of  chrysolite. 

IlHQ  first  conclusion  we  may  draw,  in  view  of  the  facts,  and 
especially  the  abrupt  transitions  in  a  flowing  stream  from  aa 
to  pahoehoe  and  the  reverse,  and  the  independence  in  kind  of 
lava,  is  that  the  difference  must  be  connected  with  some  con- 
dition in  the  region  flowed  over ;  and  the  second^  that  where 
the  transition  from  one  kind  of  stream  to  the  other  occurs, 
the  conditions  must  be  such  as  will  allow  of  extreme  liquidity 
in  one  part  (the  pahoelioe),  and  occasion  imperfect  liquidity 
or  a  pasty  state  in  the  other  (the  aci). 

It  follows  from  the  size  and  rough  character  of  the 
blocks  of  lava,  thirdly,  that  in  an  aa  stream  the  lava  must 
have  been  subjected  to  some  deeply  acting  cooling  agency  to 
have  made  a  crust  thick  enough  for  blocks  ben  to  twenty 
feet  and  more  in  dimensions, — ^  far  thicker  than  the  crust 
over  the  tunnels  in  a  pahoehoe  stream.  Fourtldy,  that  the 
cooling  was  not  from  above  downward,  as  in  the  pahoehoe, 
—  for  there  are  no  remains  of  a  pahoehoe  crust  in  the  true  aa 
field,  —  but  largely  from  below  upward ;  and  thence  comes 
the  absence  of  a  crust  and  of  the  usual  amount  of  vesicula- 
tion.  There  are  no  fragments  of  pahoehoe  among  the  aa 
fragments. 

These  four  conclusions  appear  to  lead  directly  to  ?i  fifth,  — 
that  the  region  flowed  over  and  making  aa  was  one  having 
more  or  less  of  subterranean  moisture,  since  only  moisture 
could  produce  the  partial  cooling  required  ;   not  a  superficial 


244  ERUPTIONS   OF   MOUNT   LOA  AND   KILAUEA. 

stream  of  water  that  the  lava  could  evaporate,  and  so  put 
out  of  its  way,  but  deeper  and  more  widely  spread  moisture ; 
and  not  too  much  for  the  quiet  work  of  molecular  imbibition, 
and  thereby  of  cooling  and  fracturing,  with  sometimes  a 
•'tremendous  roaring, like  ten  thousand  blast-furnaces."  The 
aa  near  Hilo  observed  by  the  author  was  over  a  valley  de- 
pression, beneath  which  such  an  amount  of  moisture  may 
well  have  existed.  Another  was  along  the  foot  of  the  meet- 
ing slopes  of  Mount  Loa  and  Kilauea,  west-southwest  of 
Kilauea.  But  the  observations  were  too  brief  to  author- 
ize a  positive  opinion  as  to  the  influence  of  the  form  of 
the  surface  in  these  cases;  and  in  others,  according  to  the 
descriptions,  the  surface  covered  by  the  aa  is  not  always 
depressed. 

There  must  be  more  or  less  moisture  in  the  dark  recesses 
of  Mount  Loa.  The  cold  summit  will  find  enough  in  the  air 
to  condense  at  most  seasons ;  and  the  percolating  rains  must 
keep  the  recesses  damp,  and  even  make  standing  water 
wherever  the  rocky  layers  favor  it.  With  subterranean 
moisture  a  hundred  yards  more  or  less  beneath  the  broad 
lava-bed  the  generated  vapors  would  ascend  into  and  through 
the  liquid  mass,  cooling  it  thus  from  below,  —  yet  not  so 
much  the  hotter  bottom,  which  receives  new  supplies  of  lava, 
as  the  portion  aljove.  The  part  solidified  would  become 
shattered  or  broken  up  by  the  tearing  steam  and  by  contrac- 
tion from  cooling  ;  and  at  the  same  time  the  flow  at  bot- 
tom would  displace  and  tumble  together  the  great  and  small 
masses,  giving  the  pile  height  because  of  the  jagged  forms  of 
the  blocks  and  the  cavernous  recesses  left  among  them.  This 
view  appears  to  meet  the  demands  of  the  facts  I  have  ob- 
served, and  all  others  so  far  as  they  have  been  published. 
But  I  present  it  only  as  a  suggestion. 

On  this  view  an  aa  stream  is  literally  an  arate  or  ploughed- 
up  lava-stream,  —  a  stream  ploughed  up  from  near  its  bot- 
tom, so  that,  although  vesiculated,  the  surface  vesiculation 


EXPLOSIVE  ERUPTIONS.  245 

fails,  as  was  well  shown  in  the  stream,  of  1880-1881  near 
Hilo  and  in  all  the  other  cases  the  author  has  examined. 

Dome-shaped  bulges  in  a  cooled  lava-stream  would  naturally 
be  common  over  the  pahoehoe  part  of  it,  where  the  stream 
begins  to  pass  to  the  aa  condition  ;  and  this  is  well  illustrated 
over  Mount  Loa. 

The  lava-halls  mentioned  on  page  10  appear  to  be  pro- 
duced through  the  rolling  movement  in  the  forward  portion 
of  the  advancing  aa  stream,  due  to  friction  at  bottom. 

Lateral  Cones. 

Lateral  cones  are  a  frequent  result  of  eruptions  on  Hawaii 
and  the  other  islands  of  the  group,  although  the  lavas  are 
basaltic.  They  occur,  as  in  other  volcanic  regions,  along  the 
courses  of  fissures,  along  a  flow  of  lava  where  fissures  for 
supplying  lavas  are  underneath  it,  and  also  in  and  about  the 
summit  crater.  Whether  a  lateral  cone  consist  of  lava- 
streams  or  of  cinders  (lapilli)  depends  on  the  supply  of  heat 
as  well  as  of  lava  in  the  vent ;  and  whether  the  cinders  make 
cinder-cones  or  tufa-cones  is  determined  by  the  supply  of 
moisture  connected  with  the  eruption,  much  descending 
moisture  giving  a  mud-like  flow  to  the  ejected  cinders, 
whence  the  low  angle  and  saucer-like  crater  of  the  tufa- 
cone.     They  are  sufficiently  described  on  pages  14,  22. 

2.     EXPLOSIVE    ERUPTIONS. 

All  the  eruptions  of  Mount  Loa  and  Kilauea  within  the 
last  sixty-seven  years  —  the  period  of  actual  history  —  have 
been,  as  has  been  stated,  of  the  ordinary  kind,  —  that  is, 
quiet  outflows.  At  each  the  lavas  of  the  crater  have  simply 
quit  work  and  sunk  out  of  sight ;  and  the  discharge  thus 
begun,  with  the  consequent  down-plunge  of  the  undermined 
floor,  was  nearly  all  there  was  of  eruption  so  far  as  the  crater 
was  concerned. 


246  ERUPTIONS   OF   MOUNT   LOA   AND   KILAUEA. 

But  traditional  history  gives  hints  of  an  eruption  in  1789 
—  a  century  back  —  of  another  kind,  an  explosive  eruption; 
and  the  results  are  visible  over  the  region  around  the  crater 
of  Kilauea,  as  already  described.  Similar  evidences  exist  of 
an  explosive  eruption  in  the  summit  crater,  as  may  be 
inferred  from  the  descriptions  of  Mr.  Brigham  (p.  194) 
and  J.  M.  Alexander  (p.  211),  as  well  as  the  earlier  of 
Captain  Wilkes,  and  also  about  the  summit  of  Hualalai. 

In  the  cases  here  referred  to,  the  ejected  material  includes 
solid  masses  of  the  basalt,  much  of  it  very  compact,  and  some 
of  the  blocks  fifty  to  a  hundred  cubic  feet  in  size.  For  such 
work,  instead  of  a  cessation  of  the  ordinary  projectile  action 
of  the  crater  and  a  quiet  discharge  of  the  lavas  when  the 
eruption  began,  there  must  have  been  an  enormous  increase 
of  projectile  power,  with  great  rendings  of  the  rocks  within 
reach  of  the  up-thrust  action.  The  eruption  was  not  a  quiet 
outflow,  but  a  catastrophic  upthrow.  Whether  accompanied  or 
not  by  an  outflow  of  lava  from  Kilauea  in  1789,  is  unknown. 

Examples  of  explosive  eruptions,  of  apparently  similar 
character,  from  Tarawera  in  New  Zealand,  and  Krakatoa,  an 
island  just  west  of  Java,  will  make  clear  what  is  meant  dis- 
tinctively by  an  explosive  eruption,  as  the  term  is  used  and 
briefly  explained  on  page  23. 

In  1886,  in  the  Tarawera  geyser  region,  after  some  earth- 
shocks,  a  projectile  eruption  of  terrific  violence  and  incessant 
detonations  began.  Scoria  and  volcanic  ashes  or  sand  were 
thrown  to  a  great  height  that  drifted  with  the  wind  and 
covered  the  country  thickly  and  far  away  with  ashes,  making 
darkness  over  a  breadth  of  several  miles  all  the  way  to  the 
sea  in  the  Bay  of  Plenty.  The  height,  as  seen  from  Auck- 
land, a  hundred  and  thirty  miles  distant,  according  to  a 
measurement  by  Mr.  Vickermann  of  the  Survey  Department 
of  New  Zealand,  was  forty-four  thousand  seven  hundred  feet. 
The  eruption  was  ended  and  the  clouds  of  dust  gone  in  six 


EXPLOSIVE   ERUPTIONS. 


247 


hours.  The  work  was  done  so  quickly  and  fiercely  that  no 
cinder-cones  were  made  by  deposits  about  the  place  of  chief 
discharge.     No  outflow  of  lavas  took  place. 


The  accompanying  map  and  explanations  will  make  the 
remarkable  Tarawera  events  more  intelligible.^     It  represents 

*  The  facts  here  o;iven  are  from  an  account  of  the  eruption  by  T.  W.  Leys,  56 
pages,  8vo,  with  maps  and  other  illustrations,  Auckland,  New  Zealand,  and  the 
"  Report "  of  S.  Percy  Smith,  Assistant  Surveyor-General,  84  pages,  8vo,  Welling- 
ton. The  height  of  the  ejections  above  given  is  cited  from  the  latter  work, 
page  29. 


248  ERUPTIONS   OF  MOUNT  LOA  AND  KILAUEA. 

the  Tarawera  geyser  reg-ion,  —  its  lakes,  mountains,  and 
other  features.  A  small  map  to  the  left  shows  the  north- 
ern New  Zealand  island  and  the  site  of  Tarawera  in 
the  N.  35°  E.  volcanic  line  of  Ruapehu,  Lake  Taupo, 
and  White  Island ;  and  White  Island  is  represented  in 
its  usual  steaming  condition  in  a  sketch  just  above.  The 
line  of  the  eruption  in  1886  extended  in  a  N.  E.-S.  W. 
course  from  Lake  Okaro  through  Mount  Tarawera  and 
Mount  Wahanga.  Lake  Rotomahana  at  the  time  of  the 
eruption  was  emptied  and  converted  into  a  region  of 
craters.  This  lake  previous  to  the  eruption  had  on  either 
side  a  geyser  basin,  and  one  of  the  famous  geyserite  ter- 
races of  New  Zealand,  the  "  Pink  Terrace  "  on  the  west  (P.  T. 
on  the  map),  and  the  larger  and  more  beautiful  "White 
Terrace  "  (W.  T.)  on  the  northeast  side,  with  the  geyser  Te 
Tarata  at  its  head.  The  outflowing  waters  of  Te  Tarata, 
descending  the  gently  sloping  surface  to  the  lake,  had  covered 
an  area  eleven  and  a  half  acres  in  extent  with  its  siliceous 
(or  geyserite)  depositions,  forming  a  descending  succession  of 
whitish  cream-colored  and  almost  porcelain-like  terraces.  A 
view  of  a  portion  of  the  terraces  is  given  in  the  left  upper 
corner  of  the  map.  At  the  eruption  both  of  the  beautiful 
terraces  were  buried  in  volcanic  mud  and  ashes,  a  mud  vol- 
cano displacing  the  geyser  basin.  A  sketch  to  the  left  (from 
a  photograph  by  Mr.  C.  Spencer)  represents  the  region  of 
the  '•  great  chasm,"  two  hundred  yards  and  more  wide,  made 
in  the  Tarawera  range  at  the  outbreak  ;  and  the  map  gives 
its  position,  and  also  the  positions  of  the  several  centres  of 
eruption  along  the  region.  The  outer  dotted  line  on  the 
map  encloses  the  part  of  the  Tarawera  region  that  was  cov- 
ered with  volcanic  ashes,  mud,  and  scoria,  and  the  inner  the 
portion  of  the  large  area  that  was  buried  beneath  mud ;  and 
the  latter  includes  the  buried  villages  of  Te  Ariki,  Moura, 
and  Wairoa,  wdiere  there  w^as  destruction  of  life  as  well  as  a 
ireneral  burial    of   houses.      Subsidences  continued    to   take 


EXPLOSIVE   EKUPTIONS.  249 

place   along  the   great  opened  fissures   for  weeks  after  the 
eruption  had  ceased. 

At  Krakatoa,  in  1883,  the  projectile  discharge  was  equally 
sudden,  and  far  more  terrible  and  destructive.  The  heiglit  to 
which  the  dust  was  carried  was  made  by  Professor  Verbeck 
fifty  thousand  feet.  It  began  in  the  early  morning  of  one 
day,  made  day  into  night  (by  its  ejections  of  ashes), for  thirty- 
six  hours,  and  left  the  sky  clear  by  the  close  of  the  next  day. 
Nothing  is  said  of  an  outflow  of  lavas. 

The  earthquakes  at  Tarawera  were  not  violent ;  they  were 
felt  to  a  distance  of  fifty  or  sixty  miles  only  ;  and  a  dozen 
miles  from  Tarawera  Mountain,  at  Rotorua,  on  the  geyser 
plains,  no  shock  was  aljle  to  upset  a  chimney  or  jar  down 
crockery  from  a  shelf.  They  were  manifestly  local,  and  had 
their  centre  near  the  surface,  —  an  effect,  not  a  cause  ;  and 
they  thus  prove  that  the  immediate  cause  of  the  eruption  was 
local.  The  facts  as  to  the  Krakatoa  earthquakes  are  similar. 
The  deafening  roar  in  each  was  made  chiefly  by  the  violent 
projectile  action,  the  incessant  detonations,  and  the  ragings 
and  thunderings  of  a  storm. 

Such  eruptions  are  of  a  wholly  different  cast  from  the 
ordinary  outbreaks  and  discharges  of  Hawaii.  The  projectile 
agent  must  gain  access  to  the  conduit  lavas  to  produce  so 
extraordinary  projectile  violence. 

The  eruption  of  Tarawera  Mountain  was  probably  brought 
about  by  the  opening  of  a  fissure  that  let  subterranean  waters 
into  the  reservoir  of  lavas  ;  for  Lake  Rotomahana,  situated  on 
the  line  of  fracture,  and  only  three  or  four  miles  distant,  lost 
its  waters,  and  probably  in  the  process  of  supplying  water  for 
the  projectile  work.  The  volcanic  mountain  had  been  long 
extinct ;  but  the  widely  distributed  geysers  and  boiling  springs 
were  testimony  to  the  existence  of  liquid  lavas  just  below  the 
reach  of  descending  atmospheric  waters.  The  geyser  lakes  of 
Rotorua  and  other  localities  became  hotter  during  the  night 

32 


250  ERUPTIONS   OF   MOUNT   LOA   AND    KILAUEA. 

of  the  eruption,  and  continued  so  afterward.  Under  such 
conditions  an  old  volcanic  mountain,  perhaps  hollow  from 
former  discharges,  might  be  burst  open  again.  Had  the  in- 
gressing  waters  passed  into  the  lava-reservoir  at  a  great  depth 
below  the  surface,  the  generated  vapors  would  almost  neces- 
sarily have  added  outflows  of  lava. 

The  volcano  of  Krakatoa  was  probably  started  into  action 
by  a  similar  incursion,  but  of  marine  waters. 

In  both  cases  there  were  enormous  chasms  and  crater-like 
depressions  made,  with  a  loss  of  the  old  foundations  and  of 
the  rocks  that  occupied  the  depressions.  But  the  facts,  while 
they  include  the  projection  of  large  stones  over  the  vicinity, 
show  positively  that  the  stones  were  few  compared  with  what 
would  be  needed  to  fill  the  great  cavities  left  in  the  region. 
The  explosive  eruption  threw  to  great  heights  fragments  of 
the  liquid  lavas  in  the  shape  of  scoria  and  sand  or  ashes,  but 
did  not  blow  off  the  solid  rocks  of  the  mountain.  The  dis- 
appearance of  these  and  the  making  of  the  cavities  are 
explained  by  the  engulfment  or  down-plunge  of  material  to 
Jill  the  space  left  empty  by  the  projectile  discharges. 

An  explosive  eruption  of  the  kind  described  is,  then,  one  in 
which  the  projectile  action,  instead  of  ceasing  at  the  time  of 
eruption,  becomes  enormously  increased ;  in  which  the  erupt- 
ing agent,  instead  of  being  roused  to  action  outside  of  the 
lava-conduit,  gains  access  to  its  interior,  and  hence  the  terrific 
boiler-like  explosion. 

For  further  explanation  I  repeat  that  the  ordinary  activity 
of  a  volcano  consists  in  the  more  or  less  high  projection  of 
cinders  or  of  liquid  lavas,  with  usually  a  great  increase  in  the 
height  as  the  crisis  of  an  eruption  approaches.  In  such  action 
there  is  nothing  of  the  explosive  work  above  described ; 
neither  is  it  entitled  to  be  called  a  state  of  eruption  ;  it  is 
only  a  state  of  activity.  Stromboli  is  perpetually  at  work  in 
the  ordinary  way,  with  great  variations  in  activity,  "  exhibiting 


EXPLOSIVE   ERUPTIONS.  251 

the  nature  of  volcanic  action  in  its  true  light ; "  but  it  is  not 
in  "  perpetual  eruption  ;  "  no  true  eruption  of  this  volcano, 
non-explosive  or  explosive,  has  been  recorded  in  recent  times. 
A  volcano  often  gasps  out  its  life  in  cinder  ejections  ;  for  this 
is  the  meaning  of  the  summit  cinder-cones  of  Kea,  Hualalai, 
and  Haleakala.  It  is  still  true,  however,  that  cases  may 
occur  in  which  it  is  difficult  to  decide  whether  the  condition 
is  that  of  ordinary  activity  or  of  true  eruption. 

The  results  of  the  projectile  eruption  of  Kilauea,  mentioned 
on  page  41,  need  not  be  here  repeated.  We  learn  from  the 
deposits  made  by  it  that  the  eruption  began  in  bombarding 
style,  —  the  projection  of  great  stones  to  a  distance  of  one 
to  two  miles,  ranoing-  to  a  hei2;ht  a  thousand  or  more  feet 
above  the  place  of  discharge,  —  and  ended  in  a  widely  ex- 
tended shower  of  scoria  and  ashes.  The  finer  material, 
besides  covering  all  the  borders  of  Kilauea,  spread  for  miles 
to  the  southeastward,  southward,  and  southwestward.  It 
constitutes,  as  I  learn  from  Mr.  Baker,  the  sand  of  the  Kau 
''desert,"  and  makes  the  bed  for  six  or  eight  miles  of  an 
excellent  carriage-road  between  the  crater  and  the  ranch 
nearly  half-way  to  Keauhou. 

The  evidence  that  the  great  stones  were  from  the  throat 
of  the  lava-conduit,  and  not  from  the  walls  of  the  crater, 
consists  in  their  comprising,  both  east  and  west  of  Kilauea, 
kinds  not  found  in  the  walls,  and  also  many  blocks  of  lava 
whose  cavities  are  lined  with  minute  crystals  of  pyroxene  and 
a  plagioclase  feldspar  (as  described  by  Prof.  E.  S.  Dana  on  a 
following  page),  which  are  proof  of  subjection  to  long-con- 
tinued heat.  The  walls  of  Kilauea  are  out  of  the  reach  of 
such  up-thrust  or  projectile  action. 

The  explosive  eruption  of  the  summit  crater  is  of  unknown 
date.  As  some  of  the  ejected  stones  are  from  fifty  pounds  to 
a  ton  in  weight,  it  was  probably  similar  in  character  to  that 
of  Kilauea  ;   but  the  facts  need  further  study. 

Explosive  eruptions  at  Kilauea  and  Mount  Loa  are  excep- 


252  ERUPTIONS   OF  MOUNT   LOA  AND   KILAUEA. 

tional  occurrences,  as  the  well-stratified  lava-made  walls  of 
Kilauea  show.  The  summit  crater,  as  described  by  visitors, 
has,  like  Kilauea,  walls  made  of  the  edges  of  lava-streams, 
without  intercalations  of  prominent  beds  of  scoria  or  other 
fragmental  material. 

An  explosive  eruption  of  a  semi-volcanic  kind,  half-way  be- 
tween volcanic  and  seismic  in  action,  is  described  on  page  23  ; 
and  Japan  has  recently  afforded  a  possible  example,  —  it  is 
the  eruption  of  Baldai-san  in  northern  Japan  on  the  15th 
of  July,  1888.  The  following  are  the  principal  facts,  from  a 
memoir  by  Mr.  Y.  Kikuchi :  ^  — 

The  volcanic  mountain  was  essentially  extinct,  though 
there  was  a  steaming  fissure  or  fumarole.  On  the  14th  the 
spring  of  a  spa  (5n  the  mountain  became  dry,  but  it  was  flow- 
ing again  the  next  morning,  —  or  that  of  the  eruption.  At 
seven  o'clock  on  the  morning  of  the  15th  there  were  the  first 
faint  earthquake  rumblings  ;  at  half-past  seven,  heavy  shocks  ; 
at  a  quarter  of  eight,  the  eruption.  A  dense  column  of 
steam  and  volcanic  dust  shot  into  the  air  with  tremendous 
noise  ;  and  fifteen  to  twenty  explosions  occurred,  each  of  a 
minute  or  more,  at  which  the  clouds  of  steam  and  dust  went 
to  a  height  of  four  thousand  to  about  thirteen  thousand  five 
hundred  feet,  which  spread  into  a  canopy  of  much  greater 
height,  making  pitchy  darkness  over  the  region.  The  dust 
was  drifted  southeastward  to  the  coast,  sixty-two  miles  ;  and 
there  the  dust-covered  area  had  a  breadth  of  thirty-one  miles. 
About  the  sides  and  base  of  the  mountain  there  was  a  tornado 
of  wind,  steam,  thunder,  lightning,  and  falling  dust  and 
rocks,  and  for  five  minutes  rain.  The  trees  blown  down  lay 
with  their  heads  away  from  the  crater.  The  rocks  fell  mostly 
about  the  top  of  the  mountain,  but  were  carried  down  in  a 
great  land-slide,  which  tlie  rain  had  evidently  promoted,  that 

*  Journal  of  the  College  of  Science,  Imperial  University,  Tokyo,  .Japan,  part  ii., 
vol.  iii. 


EXPLOSIVE  ERUPTIONS.  253 

devastated  twenty-seven  square  miles  and  buried  villages  in 
the  Nagase  valley. 

The  action  was  of  extreme  violence  ;  but  in  an  hour  the 
dust-shower  had  mainly  passed,  for  in  place  of  the  pitchy 
blackness  there  was  only  the  dimness  of  twilight  on  a  rainy 
evening;  and  in  five  hours  it  had  wholly  ceased.  The  amount 
of  dust  on  the  leeward  mountain-slope  was  less  than  a 
foot,  and  on  the  seacoast  only  traces  of  a  film.  There  was 
no  flow  of  lava ;  and  the  dust  was  not  that  from  glassy  lavas 
or  scoria,  but  resembled  the  earth  from  powdered  solid 
lava. 

The  shortness  of  duration  and  the  character  of  the  dust 
and  absence  of  lava-flow  led  Mr.  Kikuchi  to  conclude  that  no 
lava  was  concerned  in  the  eruption,  in  which  case  it  would 
merit  the  title  of  semi-volcanic  or  volcano-seismic. 

But  the  fifteen  to  twenty  explosions  of  about  a  minute 
each  suggest  a  doubt  on  this  point ;  because  such  explosions, 
in  their  high-projectile  character  and  their  apparent  regularity 
of"  interval,  are  like  those  produced  by  the  escape  of  large 
vapor  bubbles  from  very  viscid  lava  (p.  17).  Admit  the  ex- 
treme of  viscidity  which  the  vapors  could  by  accumulation 
break  through,  and  the  effects  would  be  those  of  the  Baldai- 
san  eruption,  and  not  essentially  different  from  those  of  Tara- 
wera.  Whether  this  is  the  right  view  or  not,  the  loss  to  the 
mountain  —  which  is  roughly  estimated  by  Mr.  Kikuchi  at 
2,782,000,000  tons  —  might  have  been  due  mainly  to  the 
down-plunge  following  the  ejection.  The  projectile  vapors 
would  have  expended  their  energies  in  work  where  gen- 
erated, steamboiler-like ;  after  passing  into  the  air  above 
they  would  have  driven  ineffectually  against  volcanic  peaks 
of  solid  lava. 


254  VOLCANIC   ACTION   ON   HAWAII. 


11.   Metamorphism  an  Effect  of  Volcanic  Conditions. 

The  projected  rocks  of  the  region  about  Kilauea  are  a 
prominent  source  of  evidence  as  to  metamorphism  by  means 
of  volcanic  heat,  as  remarked  on  page  178 ;  and  other  facts 
of  like  import  are  derived  from  the  lava-stream  tunnels  and 
caverns.  The  rocks  referred  to  and  those  also  of  the  lavas 
generally,  as  well  as  the  cave-products,  are  described  by  Mr. 
E.  S.  Dana  in  a  following  part  of  this  volume.  I  briefly 
mention  here  a  few  of  the  facts  that  have  a  special  bearing 
on  metamorphism. 

1.  The  minute  crystals  in  the  cavities  of  the  ejected 
masses,  instead  of  being  zeolites,  such  as  exposure  to  the 
weather  or  to  moderately  hot  vapors  might  have  produced, 
are  proved  by  Mr.  Dana,  as  has  been  stated,  to  be  identical 
with  the  anhydrous  constituents  of  the  lava.  Minute 
transparent  acicular  crystals  have  given  him  the  angles  of 
pyroxene  ;  white  rhombic  tables,  the  characters  of  labra- 
dorite  ;  and  besides,  there  are  brilliant  iron-black  octahedrons 
of  mag:netite  and  tables  of  hematite  or  titanic  iron.  These 
are  the  constituents  of  the  basalt,  and  all  of  them,  except 
the  less  constant  one,  clirysolite. 

2.  The  caves  and  tunnels  of  Kilauea  and  of  the  Mount  Loa 
lava-stream  of  1880-1881  have  been  described  as  affording 
stony  stalactites,  remarkable  for  their  slender  pipestem-like 
size  and  form,  some  of  them  twenty  to  thirty  inches  long; 
yet  these  stony  stalactites  are  essentially  identical  in  con- 
stitution with  the  rock  of  the  lava-stream,  even  to  the  laths 
of  labradorite,  as  was  suspected  at  the  time  of  the  visit  to 
the  tunnel,  and  as  has  been  proved  by  the  microscopic  investi- 
gation of  Mr.  E.  S.  Dana,  who  found  also  that  the  crystals 
of  the  cavities  are  of  pyroxene  and  labradorite  as  in  the 
ejected  blocks. 

The   origin    of    the    stalactites   of   the   tunnels    and   their 


METAMORPHIC    RESULTS.  255 

crystallizations  is  due,  as  I  state  in  my  "Expedition  Report" 
(p.  201),  to  "the  action  of  steam  on  the  roof  of  the  cavern." 
In  the  case  of  the  tunnels  the  flowing  lavas  left  behind  a 
chamber  filled  with  superheated  steam,  and  under  its  action 
tlie  solution  and  recrystallization  went  forward. 

This  reproduction  of  the  basalt  and  the  making  of  the 
crystals  in  geodes,  or  as  linings  of  fissures,  are  examples  of 
metamorphic  work.  It  is  metamorphism  of  the  crystallinic 
kind,^  —  the  same  which  takes  place  when  a  feldspathic 
sandstone  is  converted  into  granite  or  granulyte,  or  when 
calcyte  is  changed  into  marble.  It  is  simply  a  reproduction 
of  the  basalt  by  superheated  vapor. 

3.  The  ejected  blocks  about  Kilauea  instruct  us  on  an- 
other point  of  much  geological  importance.  They  show 
that  the  throat  of  a  volcano  is  necessarily  a  region  of  meta- 
morphic action.  It  is  a  region  of  continued  heat ;  and 
heat  always  works  change  when  moisture  is  present.  The 
special  results  of  this  conduit  metamorphism  at  Kilauea  are 
described  in  the  chapter  on  the  rocks.  The  minerals  made 
are,  as  in  the  stalactites,  only  the  minerals  of  a  basalt  or  dole- 
ryte,  as  augite,  labradorite,  magnetite,  hematite  ;  but  they 
are  put  in  groups  of  crystals  in  cavities  and  through  the 
mass  of  the  rock.  Under  like  conditions,  an  Archoean  lime- 
stone or  other  Archaean  rock  containing  chondrodite,  spinel, 
vesuvianite,  scapolite,  anorthite,  nephelite,  biotite,  might  lead 
to  the  production  of  recrystallized  chondrodite  (humite),  spi- 
nel, vesuvianite,  scapolite  (meionite),  anorthite,  nephelite,  bio- 
tite (or  meroxene)  as  metamorphic  results ;  and  in  just  the 
situation  where  an  explosive  eruption  might  detach  masses 
and  bring  them  up  to  the  light.  It  is  noteworthy  that  the 
above  minerals  of  the  ejected  blocks  about  Somma  —  which 
have  long  been  regarded  as  throat  minerals  of  Vesuvius 
crystallized  by  the  volcanic  heat,  as  held  by  Scacchi  —  are 

^  "  On  Terms  applied  to  Metamorphism,"  American  Journal  of  Science,  1886, 
3d  series,  xxxii.  70. 


256  VOLCANIC   ACTION    ON   HAWAII. 

kinds  that  are  characteristic  of  Archsean  rocks  and  especially 
of  an  Archgean  limestone,  rocks  which  may  underlie  the  later 
limestones  and  other  strata.  There  is  little  assumption,  there- 
fore, in  saying  that  some  of  these  crystallizations  illustrate 
specifically  crystallinic  metamorphism,  though  others  may  be 
of  the  metachemic  kind,  that  is,  products  of  chemical  change. 

III.   Form  of  Mount  Loa. 

Mount  Loa  differs  from  most  volcanic  mountains  in  having 
a  double  curvature  in  its  profile,  convex  above  and  concave 
below,  owing  to  the  flattening  and  widening  of  its  summit 
and  the  spreading  of  its  base.  It  is  the  broad  flattened  sum- 
mit which  gives  so  vast  bulk  to  a  mountain  of  its  altitude. 
In  accordance  with  the  principles  illustrated  on  page  11, 
the  dome-like  shape  has  evidently  been  produced  by  the  very 
work  that  has  been  going  on  during  the  last  sixty-five  years,  — 
eruptions  not  from  the  summit,  but  from  points  one  sixth  to 
one  eighth  of  the  height  from  the  summit.  The  top  has  thus 
been  widened  until  it  is  almost  a  plane  surface  for  a  distance 
of  one  to  two  miles.  At  the  same  time  there  have  been 
basal  eruptions  tending  to  spread  the  base  above  the  sea- 
level.  This  effect  is  very  marked  to  the  southeastward  of 
Kilauea. 

Owing  to  the  nearly  complete  absence  of  cinder-ejections, 
the  summit  of  Mount  Loa  fails  of  the  most  common  means  of 
growth  in  height  with  tapering  top ;  and  this  is  a  prominent 
source  of  the  difference  between  it  and  most  other  volcanic 
mountains.  Mount  Kea  secured  its  greater  height  and 
tapering  top  by  the  cinder-ejections  which  ended  its  period 
of  activity. 

Another  cause  tending  to  modify  the  shape  of  the  moun- 
tain is  that  producing  fractures  and  subsidences.  Its  effects 
are  seen  about  the  great  craters,  and  still  more  pronounced 
about  the  borders  of  the  island.  *  The  former  action  aids  in 


FORM   OF   MOUNT  LOA.  257 

making  summits  broad  and  flat,  wiiile  the  latter  works  di- 
rectly against  the  widening  of  the  coast  region.  It  makes 
the  greatest  fractures  nearly  jjarallel  vjith  the  coast,  and  dro2)s 
the  coastward  block  ;  it  thus  tends  to  shorten  the  radius  of 
that  part  of  the  mountain,  and  put  precipices  into  its  profiles, 
increasing  thereby  the  mean  slope.  Two  such  walls  in  southern 
Hawaii  cross  the  road  between  Keauhou  and  Kilauea,  one 
about  a  mile  and  a  half  from  the  coast  and  the  other  three 
miles  ;  they  are  marked  features  before  the  traveller  in  his 
ride  from  the  coast  to  the  volcano.  These  faultings  seem  to 
be  a  reason  for  the  concavity  in  the  southern  coast-line  from 
Keauhou  westward,  and  for  the  short  distance  in  that  direc- 
tion from  the  summit  to  the  coast.  Other  great  fault-planes 
exist ;  but  the  government  map  of  the  island  should  be  com- 
pleted before  the  facts  can  be  satisfactorily  discussed. 

The  following  are  the  mean  slopes  of  Mount  Loa  from  the 
summit  along  different  radii.  The  distances  made  the  basis 
of  the  calculations  are  taken  from  the  Government  map. 

S.  S.  W.  to  the  southern  cape  1  :  13-1=4°  22' 

S.  E.  by  S.  to  the  indented  Kapapala  shore  1  :  9=:  6°  20' 

S.  E.  to  foot  of  slope  W.  of  Kilauea  1  :  9-12  =  6°  15' 

E.  N.  E.  to  shore  at  Ililo  1   :  14-86  =  3°  51' 

W.  by  8.  to  western  shore  1  :  8-11=6°  43' 

N.  by  E.  to  plain  between  Loa  and  Kea       1  :  9  to  1  :  10  =  5°  50'  to  6° 

In  a  circle  of  five  miles  around  the  summit  crater  the  mean 
slope  is  about  three  degrees  ;  the  mean  depression  to  the  east- 
ward at  the  perimeter  of  the  circle  is  about  fourteen  hundred 
feet.  It  is  interesting  also  to  note  that  the  slope  of  the  eccen- 
tric cone  of  the  bottom  of  Kilauea  from  Haleraa'uma'u  north- 
eastward —  a  result  of  the  outflows  of  the  Great  Lake  in 
1885  —  is  about  1  :  50  or  1°  9'. 

From  Kilauea  to  the  eastern  cape,  twenty-eight  miles,  the 
slope  is  1:  36i  =  r  35'. 

The  fact  that  Mount  Loa  as  well  as  Kilauea  was  made  over 
a  great  fissure  has  given  an  oblong  and  approximately  elliptical 

33 


258  VOLCANOES   OF  HAWAII. 

or  ovoidal  form  to  all  the  upper  contour  lines  of  Mount  Loa. 
Further,  the  bend  in  the  longer  axis  of  the  summit  crater, 
making  the  concavity  to  the  eastward,  is  also  expressed,  ac- 
cording to  the  large  Government  map,  in  the  form  of  the 
upper  part  of  the  dome. 

At  what  period  in  its  history  Mount  Loa  left  off  super- 
fluent  discharges  and  took  to  having  only  the  effluent,  or 
those  through  fissures,  it  is  impossible  to  say.  But  as  the 
walls  both  of  Kilauea  and  the  summit  crater  are  made  up 
of  the  edges  of  lava-streams  to  the  very  top,  it  would  ap- 
pear that  summit  overflows  from  the  crater  may  have  con- 
tinued in  each  to  a  comparatively  recent  time.  It  is  remark- 
able that  the  north  and  west  walls  of  Kilauea,  which  show 
well  the  stratification  from  top  to  bottom,  have  almost  no 
intersecting  dikes. 


D.     RELATIONS   OF   KILAUEA   TO   MOUNT   LOA. 

The  position  of  Kilauea  "on  the  flanks  of  Mount  Loa," 
ninety-five  hundred  feet  below  the  level  of  the  summit, 
plainly  suggests  the  idea  of  its  later  and  dependent  origin. 
If  the  two  were  begun  at  the  same  time,  why,  it  is  naturally 
asked,  should  not  Kilauea  have  approximately  the  same  size 
as  Mount  Loa  ?  With  the  same  time  to  grow  in,  and  a  dis- 
tance between  the  two  nearly  equal  to  that  between  Kea  and 
Loa,  and  a  crater  as  large  and  still  active,  would  it  have 
stopped  at  less  than  one  third  the  height,  and  have  raised  its 
summit  only  three  hundred  feet,  at  the  best,  above  the  Mount 
Loa  slopes  ? 

Several  of  the  islands  —  Oahu,  Molokai,  Maui,  and  perhaps 
also  Kauai  —  consist  of  two  volcanoes  united  at  base,  or  are 
volcanically  twins ;  and  Hawaii  is  a  double  twin,  one  couplet 
consisting  of  Kohala  and  Kea,  and  the  other  of  Hualalai  and 
Loa,  provided  Kilauea  is  subordinate  to  Mount  Loa.     In  all 


RELATIONS   OF   KILAUEA   TO   MOUNT   LOA. 


259 


the  twins  the  eastern  of  the  two  combined  volcanic  mountains 
is  the  larger.  But  Kilauea,  although  the  eastern  on  Hawaii 
and  the  easternmost  of  the  whole  group,  is  one  of  the 
smallest.  The  greater  size  of  the  eastern  volcano  in  a 
couplet  has  come  from  its  continuing  longer  in  action  ;  and 
this  is  proved  not  simply  by  the  size,  but  also  by  the  evi- 
dence of  long  extinction,  and  therefore  long  exposure  to  de- 
nuding agents,  in  the  western  mountain.  There  is  other 
evidence,  also,  in  the  fact  that  the  slopes  of  the  western  of 
the  mountains  in  each  twin  island  are  partly  buried  by  the 
more  recent  lavas  of  the  eastern,  —  Kohala  by  those  of  Kea, 
western  Oaliu  by  those  of  eastern.  The  order  in  time  of 
extinction  thus  derived,  which  my  "Report"  presents,  is  as 
follows  :  — 


1.  Kauai. 

2.  Southwest  Oahu. 

3.  Western  Maui. 

4.  Kohala,  on  northwest  Hawaii. 

5.  Northeast  Oahu. 


6.  East  Maui. 

7.  Mount  Kea,  Hawaii. 

8.  Mount  Hualalai,  Hawaii. 

9.  Mount  Loa  and  Kilauea. 


oO 


OAHU 

^---^ — '^^ — v^  MAUI 

LANAlf    \  r®^V"     \ 

V )  ^ — ilfaleafcala 

KAHOOLAWE  O  ^^— ^ 

HAWAII  y^^ 
Hualalai 


Here,  again,  the  system  seems  to  require  that  Kilauea 
should  be  made  an  appendage  to  Mount  Loa.  The  above 
diagram  is  drawn  to  show  these  relations  of  the  constituent 


260  VOLCANOES   OF    HAWAII. 

volcanoes.^  Kea  and  Hiialalai  are  made  in  it  to  spread 
too  far  over  Kohala,  the  central  region  of  which  should 
have  been  left  uncovered  ;  but  the  general  idea  conveyed 
is  right. 

On  these  grounds  the  conclusion  was  drawn  by  the  author 
in  1840  that  Kilauea  originated  over  a  great  fissure  made  at 
some  Mount  Loa  eruption. 

The  close  relation  of  the  two  volcanoes  is  made  evident, 
further,  by  the  recent  investigation  of  the  rocks  reported 
upon  beyond.^  Prof.  E.  S.  Dana's  examinations  have  found 
the  rocks,  so  far  as  studied,  to  be  the  same  kind  of  basalt  in 
mineral  constitution  and  in  all  details  of  composition ;  as  high 
in  specific  gravity  ;  as  varied  in  the  proportions  of  chrysolite 
from  apparently  none  to  nearly  half  chrysolite  ;  as  varied  in 
texture  from  the  lightest  scoria  to  the  compact  kind  in  which 
only  microscopic  vesicles  are  distinguishable  when  any ;  as 
generally  free  from  glassy  portions,  glass  being  rarely  dis- 
tinscuished  in  even  the  basalt  of  the  most  recent  lava- 
streams;  and  as  subject  to  the  alteration  to  feathery  forms 
of  augite. 

This  conclusion  is  not  accepted  in  the  report  of  Mr.  W.  T. 
Brigham,  Capt.  C.  E.  Button,  or  Mr.  W.  L.  Green. 

1.  The  apparent  independence  of  action  in  Kilauea  is  one 
of  the  opposing  arguments  ;  and  it  is  a  strong  one.  There  is 
commonly  no  sympathy  in  their  movements,  although  both 
have  craters  of  unusual  magnitude  which  are  in  frequent 
eruption  and  essentially  in  continuous  activity,  and  although 
the  open  vent  of  Kilauea  with  its  boiling  lavas  is  but  3,600 
feet  above  the  sea-level  (in  1840  but  3,000  feet)  against  12,900 
•  for  the  Mount  Loa  crater.  They  have  had  some  nearly  simul- 
taneous eruptions  ;  but  the  larger  part  of  the  greater  erup- 
tions of  Mount  Loa  have  taken  place  while  the  lava-lakes  of 
Kilauea  were  in  a  state  of  undisturbed   ebullition.     There 

*  Exploration  Expedition  Report,  p.  283. 
2  Page  318. 


RELATIONS   OF    KILAUEA   TO   MOUNT    LOA. 


261 


was  remarkable  harmony  of  action  in  the  earthquake  erup- 
tions of  the  two  in  1868  ;   but  it  has  been  shown  that  the 
earthquakes  which  set  off  Kilauea  were  of  Mount  Loa  origin, 
made    through    Mount    Loa 
fires,  and  having  their  cen- 
tre over  thirty  miles  distant 
from    Kilauea    beneath    the 
Mount  Loa  slopes ;  and  this 
harmonious  action  therefore 
does  not  indicate  much  sym- 
pathy between  the  two  fiery 
neighbors,   after  all. 

2.  In  August,  1887,  the 
author's  examination  of  the 
walls  of  Kilauea  on  the  side 
toward  the  summit  of  Mount 
Loa  resulted    in   discovering^ 


no  great  dikes  or  other  signs  of  former  dependence  on 
Mount  Loa.  This  evidence  is  not  of  great  value,  because 
the  wall    now  exposed   to  view  may   be  far  inside   of   the 


^62  VOLCANOES   OF   HAWAII. 

wall  of  the  greater  original  crater,  just  as  the  wall  of 
the  "  lower  pit "  of  1840,  which  was  in  general  without 
dikes,  was  inside  of  the  corresponding  wall  of  1832  and 
1823,  and  of  the  outer  wall  of  the  crater  for  each  of  these 
periods, 

3.  The  distance  between  the  craters  of  Mount  Loa  and 
Kilauea  is  about  the  same  that  exists  between  the  other 
great  volcanic  centres  of  the  islands.  But  this  argument, 
urged  by  Mr.  Green,  is  indecisive,  especially  in  view  of  the 
small  height  of   Kilauea. 

4.  A  new  argument  may  be  derived  from  the  relation  of 
Kilauea  to  the  two  j^ct'^^ci^iel  ranges  of  islands  constituting  the 
Hawaiian  group.  These  ranges  are  indicated  on  the  accom- 
panying map  by  the  lines  connecting  the  islands.  The  north- 
ern, or  "  Kea  range,"  includes  northeastern  Oahu,  eastern 
Molokai,  eastern  and  western  Maui,  and,  on  Hawaii,  Kohala 
and  Kea ;  the  soutlwrn,  or  "•  Loa  range,"  comprises  south- 
western Oahu,  western  Molokai,  Lanai,  Kahoolawe,  Mount 
Hualalai,  and  Mount  Loa,  with  Lua  Pele  (or  Kilauea)  on 
the  flanks  of  Mount  Loa.^  The  Loa  and  Kea  ranges  have  a 
mean  trend  of  about  S.  60°  E.  To  the  eastward  the  line  of 
each  range  inclines  increasingly  to  the  southward.  The 
northern,  in  its  course  from  Maui  through  Kohala  to  the 
summit  of  Kea,  becomes  S.  45''  E.  in  trend  ;  and  the  southern 
from  Kahoolawe  to  Hualalai  and  the  summit  of  Mount  Loa 
has  nearly  the  same  course. 

Now,  the  line  of  the  northern  or  Kea  range,  if  continued  on 
with  only  a  little  m.ore  southing,  strikes  Kilauea  ;  while  that 
of  the  southern  points  southward  far  away  from  it.  Kilauea 
appears^  therefore,  to  lelong  to  the  Kea  or  northern  range,  and 
not  to  the  Loa  or  southern  range  ;  and  if  so,  it  is  not  an 
appendage  to  the  latter  range,  or  to  Mount  Loa,  one  of  its 
volcanoes. 

There  is  seemingly  a  ''  clincher  "  to  this  argument.     The 

1  E.\:i)lori!i<,'  Expeilition  Geolooical  Report,  ji.  157. 


RELATIONS   OF   KILAUEA   TO   MOUNT   LOA.  263 

great  craters  are  generally  situated  over  the  intersection  of 
two  fissures,  one  of  which  is  the  course  of  the  range  of  islands 
and  the  other  transverse  to  it,  as  stated  by  Mr.  J.  M.  Alex- 
ander.^ Now,  the  line  of  the  Kea  range  strikes  Kilauea  very 
nearly  at  right  angles  to  its  longer  diameter,  in  accordance 
with  this  rule.  Further,  the  line  of  the  Loa  range,  or  better 
a  line  from  the  summit  of  Hualalai,  strikes  Mount  Loa  pre- 
cisely in  the  same  way.  This  coincidence,  which  the  map 
well  shows,  seems  therefore  to  prove  that  Kilauea  belongs 
to  the  Kea  range  and  not  to  the  Loa.  The  substitution  of  a 
line  from  Hualalai  for  that  from  Kahoolawe  is  reasonable, 
because  the  fissures  over  which  the  Hawaiian  volcanoes  were 
formed  were  probably  independent  for  each  island,  though 
conforming  to  the  general  system.  The  summits  of  Kea  and 
Loa  are  corresponding  points  in  the  two  ranges,  and  Kilauea 
is  an  advance  of  one  stage  beyond  Kea  in  the  Kea  range ;  it 
is  owing  to  this  that  the  longer  diameters  of  the  Loa  crater 
and  Kilauea  make  an  angle  with  one  another  of  about  32°. 
It  is  interesting  to  note,  also,  that  the  longer  diameter  of  the 
crater  of  Mount  Loa,  or  especially  its  southern  half,  points  to 
the  top  of  Mount  Kea ;  and  that  a  line  from  Loa  to  Kea  is 
nearly  parallel  to  one  between  Hualalai  and  Kohala ;  so 
that  the  parallelogram  enclosed  has  angles  nearly  of  70° 
and   110^- 

^  American  Journal  of  Science,  1888,  xxxvi.  38. 

2  Mr.  W.  L.  Green,  in  his  "  Vestiges  of  the  Molten  Globe,"  brings  forward  a 
theory  for  the  origin  of  the  general  features  of  the  globe,  which  supposes  its  defor- 
mation from  contraction  on  cooling  to  have  developed  feature  lines  crossing  at  angles 
of  60°,  —  a  "  tetrahedral  symmetry," — and  subordinately  to  these  other  lines  at 
right  angles  to  the  sides  of  the  triangle.  His  map  of  the  Hawaiian  Islands,  which 
is  covered  with  triangles,  represents  one  of  these  lines  as  meridional,  and  one  accord- 
ant, consequently,  with  the  mean  trend  of  the  group,  or  nearly  so.  On  page  147  of 
his  work,  it  is  stated  that  confirmation  of  his  hypothesis  is  seen  in  the  fact  "  that 
the  direction  of  the  longer  axis  of  the  elliptical  craters  of  Mokuaweoweo  and  Kilauea 
is  N.  30°  E."  But  the  facts  appear  to  be  that  the  longer  axes  of  the  two  craters 
diverge  32°  in  direction,  and  that  of  Kilauea  has  nearly  the  course  N.  52°  E.  More- 
over, the  trend  of  the  island  volcanoes  of  the  group  varies  greatly  in  going  from  one 
end  of  the  range  to  the  other;  and  in  this  the  Hawaiian  is  like  other  ranges  over 
the  ocean. 


264  VOLCANOES   OF   HAWAII. 

Notwithstanding  the  independence  of  Kihiuea,  there  may 
still  at  times  be  evidence  of  some  sympathy ;  for  the  two 
great  active  lava-columns  are  only  twenty  miles  apart. 

The  evidence  does  not  make  it  certain,  however,  that 
Kilauea  originated  as  early  in  the  history  of  Hawaii  as 
either  Kea  or  Loa ;  for  the  original  fracture  extending  in 
that  direction  from  Kea  may  at  first  have  been  sufficient 
only  to  let  out  a  flood  of  lavas,  and  subsequently  have  been 
further  opened  and  crossed  by  a  greater  fissure,  so  as  to 
produce  over  it  the  permanent  Kilauea  vent. 

5.  Whatever  the  fact  as  to  the  relations  of  Kilauea  and 
Mount  Loa,  I  believe  they  still  sustain  my  old  conclusion 
that  volcanoes  are  not  safety-valves  ;  ^  for  •'  if  while  Kilauea 
is  open  on  the  flanks  of  Mount  Loa,  lavas  still  rise  and  are 
poured  out  at  an  elevation  of  ten  thousand  feet  above  it, 
Kilauea  is  no  safety-valve  even  for  the  area  covered  by  the 
single  mountain.  Volcanoes  are  indexes  of  danger ;  they 
point  out  the  portions  of  the  globe  which  are  most  subject  to 
earthquakes."  The  safer  place  is  somewhere  else.  And 
among  volcanic  mountains,  one  that  is  really  dead  is  a  pref- 
erable neighbor  to  the  volcano  that  has  been  smouldering 
from  time  immemorial.  For  the  emission  of  heat  by  hot 
springs,  geysers,  or  fumaroles  within  a  dozen  miles  is  pretty 
good  evidence,  as  at  Tarawera,  New  Zealand,  that  liquid 
rock  is  at  no  very  great  depth  below,  —  too  deep  to  re- 
ceive from  descending  waters  the  moisture  that  may  con- 
tribute energy  to  the  fires  and  produce  volcanic  activity, 
but  not  too  deep  to  be  opened  on  an  extreme  emergency, 
so  as  to  give  entrance  to  a  flood  of  waters  for  the  most 
terrific  of  eruptions. 

1  Exploring  Expedition  Report,  p.  221. 


MOUNT  LOA  AND  VOLCANOES  OF  THE  VESUVIUS  TYPE.     265 


E.    CONTRAST  BETWEEN   MOUNT  LOA  AND  VOLCANOES 
OF   THE  VESUVIUS   TYPE. 

The  marked  contrast  between  volcanoes  of  the  Mount  Loa 
and  Vesuvius  types  based  on  the  liquidity  of  the  lava,  making 
Mount  Loa  discharges  to  be  almost  solely  outflows  and  those 
of  Vesuvius  both  upthrows  of  cinders  and  outflows  of  lava, 
has  been  sufficiently  explained  on  page  143.  With  this  ex- 
ception, the  contrast  as  to  their  eruptions  as  well  as  to  their 
ordinary  action  is  far  less  than  is  generally  supposed. 

There  is  no  reason  to  regard  the  forces  as  different  in  kind 
or  mode  of  action.  If  the  outside  waters  gain  slow  access 
at  depths  below  to  the  lavas  for  the  ordinary  action  of  a 
volcano  in  Hawaii,  they  can  at  Vesuvius  ;  and  the  force  from 
the  escaping  vapors  that  in  this  ordinary  action  will  make 
jets  of  lava  of  thirty  to  six  hundred  feet  will  make  jets 
of  cinders  of  far  greater  height.  Moreover,  as  the  erupting 
force  at  Mount  Loa  in  non-explosive  eruptions  is  not  due  to 
vapors  inside  the  lava-column,  since  it  does  its  chief  fracturing 
part-way  down,  and  sometimes  far  down,  the  mountain  instead 
of  about  the  summit,  and  causes  a  quiet  condition  in  the 
crater  instead  of  violent  action,  so  it  is  essentially  at  Vesu- 
vius. In  exjjlosive  eruptions  at  Vesuvius,  on  the  contrary,  the 
explosive  force  may  be  due  to  vapor-generation  inside  of  the 
lava-caldron,  the  projectile  action  being  vastly  increased,  as 
at  Tarawera  in  1886  and  Krakatoa  in  1883. 

As  the  observations  at  Vesuvius  of  Scacchi  ^  and  others  have 
shown  (and  my  own  two  visits  to  Vesuvius,  one  just  before  an 
eruption,  enable  me  to  appreciate),  high-lava  mark  in  the  vol- 
cano, or  that  of  readiness  for  a  discharge,  is  attained  in  the 
same  way  essentially  as  in  Kilauea.     After  a  down-plunge  fol- 

^  Scacchi,  A.,  Eruzione  Vesuviano  del  1850  e  1855,  Napoli,  1855,  in  which  the 
changes  from  1840  to  1855  are  carefully  described. 

34 


266  CONTRAST   BETWEEN   MOUNT   LOA 

lowing  an  eruption  (as  a  result  of  the  undermining),  leaving 
the  crater  hundreds  of  feet  deep  and  the  upper  extremity  of 
the  lava-column  at  a  still  lower  level,  work  again  soon  com- 
mences, provided  the  lava-column  were  not  so  profoundly 
cooled  off  by  the  aggressive  waters  and  vapor-generation  as 
to  be  left  too  deeply  buried.  For  a  while  the  fractures  in 
the  bottom  of  the  crater  emit  only  vapors.  Later,  projectile 
action  begins  at  one  or  more  points,  making  conical  cinder- 
deposits  by  the  pericentric  action,  with  now  and  then  an  addi- 
tion to  the  inside  accumulations  from  small  outflows  of  lava 
about  the  bases  of  the  cones  or  from  their  vents.  The  throws 
of  cinders  and  flows  of  lava  are  kept  up  at  irregular  inter- 
vals, and  the  level  of  the  floor  rises.  After  the  height  within 
has  become  much  increased,  small  fissures  occasionally  open 
through  the  outside  slopes  and  let  out  some  lava;  but  the 
ejections  are  mostly  retained  inside,  except  in  the  later 
period  of  progress,  when  some  of  the  high-thrown  cinders 
may  fall  over  the  outside  of  the  mountain  or  drift  away  with 
the  wind.  Years  pass,  and  finally  the  crater's  bottom,  bear- 
ing a  large  cinder-cone,  or  more  than  one,  reaches  that  high 
level  in  which  it  becomes  actually  the  summit-plain  of  Vesu- 
vius; and  the  fires  are  visible  in  the  cracks  of  the  plain, 
because  the  liquid  lavas  are  not  far  below  it. 

The  author  would  refer  the  reader  to  a  cut  representing 
Vesuvius  in  the  condition  here  described,  contained  in  his 
"  Text-book  of  Geology,"  made  from  his  sketch  in  1834,  and 
to  a  paper  in  the  "  American  Journal  of  Science  "  for  1835.^ 
At  his  visit  of  that  time  he  found  the  summit  of  Vesuvius  a 
plain,  —  the  altopiano.  —  with  a  small  active  cinder-cone  near 
its  centre.  Only  five  years  before,  in  1829,  the  crater  was 
reported  to  be  two  thousand  feet  deep,  —  "  an  immense  and 
frightful  gulf,"  ^  as  viewed  from  the  narrow  margin.  In  the 
short  interval  high-lava  mark  had  been  reached.     A  red  heat 

1  Vol.  xxvii.  (1835),  p.  281. 

2  Wines,  Two  Years  and  a  Half  in  the  Navy. 


AND  VOLCANOES   OF  THE  VESUVIUS  TYPE.  267 

existed  ten  to  twenty  inches  down  in  many  fissures  over  the 
plain  ;  and  at  one  place  a  stream  of  lava,  four  to  five  feet 
wide,  emerged  and  flowed  away  down  the  mountain.  But 
the  floor  was  safely  walked  over,  and  the  small  spiteful 
cinder-cone  was  ascended,  the  work  going  on  quietly,  as  at 
Kilauea.  The  mountain  was  charged,  and  a  month  later,  in 
August,  a  great  eruption  occurred,  the  lava  flowing  eastward 
far  toward  Torcigno.  M.  Abicli,  —  who  was  then,  as  he  re- 
ports, studying  the  volcano,  —  after  describing  the  top  plain 
and  its  cinder-cone  as  seen  by  him  before  the  event,  states 
that  at  the  eruption  that  platform  of  lava  subsided  and 
opened  to  view  the  interior  of  the  large  cone.^ 

Thus  the  processes  are,  as  in  Kilauea:  (1)  filling  ;  (2)  dis- 
charging ;   (3)  collapsing. 

How  far  the  ascensive  force  in  the  lava-column  contributes 
to  the  change  of  level  in  the  floor  of  Vesuvius  nobody  knows. 
The  question  has  hitherto  hardly  been  considered.  It  prob- 
ably does  its  part ;  for  the  liquid  lava  rises  with  the  rising 
floor,  following  it  closely. 

With  the  column  of  liquid  lava  thus  lengthened,  making 
the  mountain  ready  for  a  discharge,  the  danger  of  catastrophe 
is  great  for  the  same  reasons  as  at  Kilauea.  But  the  danger 
is  greater  than  there.  It  is  greater  because  the  forces  from 
vapor-generation  and  hydrostatic  pressure  have  a  weaker 
mountain  to  deal  with,  —  one  that  has  steeper  sides,  and 
therefore  thinner  walls  to  the  lava-caldron,  and  walls  that 
are  partly  cinder-made.  It  is  greater  because  also  of  the 
nearness  of  the  lava-column  to  the  sea,  the  distance  being 
only  four  miles,  while  in  the  case  of  Kilauea  it  is  over  nine 
miles,  and  in  Mount  Loa  over  twenty ;  so  that  at  Vesuvius 
water  from  two  sources,  the  sea  and  the  land,  is  close  by. 

Causes  that  produce  earthquakes  may  make  a  rent  in  the 
Vesuvian  lava-conduit  that  will  let  in  water  for  an  explosive 
eruption  ;   but  usually  it  opens  the  way,  as  at  Mount  Loa,  for 

^  Erlaut.  Abbild.  Vesuvius  uud  Aetna,  Berlin,  1837. 


268  MOUNT  LOA  AND  VOLCANOES  OF  THE  VESUVIUS  TYPE. 

a  comparatively  quiet  escape  of  lava,  however  disquieting  the 
event  may  be  to  deluged  villages. 

The  loss  by  upthrows  and  outflows  tends  to  produce  a  sink- 
ing or  down-plunge  of  the  floor  of  the  crater,  and  some  fall  of 
its  walls  to  the  new  bottom,  as  in  Kilauea.  At  the  Kilauea 
eruption  of  1886  the  outflow  drew  off  the  lavas  of  a  lava- 
lake  half  a  mile  in  diameter ;  the  crust  of  lava  that  covered 
the  borders  of  the  lake,  along  with  portions  of  the  walls, 
consequently  sank  down,  and  the  cavity  or  crater  left  by  the 
discharge  was  half  a  mile  across  and  between  five  and  six 
hundred  feet  in  depth.  This  is  little  different  from  the  ordi- 
nary event  in  Vesuvius,  except  that  the  loss  by  the  discharge 
at  Kilauea  is  almost  solely  by  outflow,  and  no  high,  weak- 
sided  cone  surrounds  the  vent  to  suft'er  from  the  disaster.  It 
is  true  that  the  Kilauea  lava-lake  in  the  eruption  just  referred 
to  occupied  only  a  small  part  of  the  great  crater.  But  its 
diameter  was  as  large  as  the  lava-caldron  of  Vesuvius  has 
been  before  any  of  its  modern  eruptions ;  and  the  movements 
in  the  lake  were  the  same  that  would  take  place  were  all 
Kilauea  one  great  lake.  "At  the  eruption  of  May  31,  1806," 
says  Signor  G.  Zorda,  "  a  considerable  part  of  the  summit 
fell  into  the  volcanic  abyss ; "  and  facts  enough  are  reported 
to  show  that  the  same  took  place  at  the  grander  eruption 
of  1822.  But  in  the  smaller  eruptions  of  Vesuvius  the 
altopiano  often  undergoes  little  change,  because  the  un- 
dermining is  not  sufficient  for  more ;  and  after  a  while 
cinder-eruptions  may  be  resumed ;  consequently  after  such 
eruptions,  as  Scacchi  observes,  the  heiglit  of  Vesuvius  may 
become  increased.  This,  again,  is  parallel  with  the  facts  in 
Kilauea. 

Explosive  eruptions  might  prove  much  more  disastrous 
to  a  Vesuvian  cone  than  to  one  of  massive  Mount  Loa 
style ;  but  not  because  the  explosion  has  the  power  of  blow- 
ing off  the  mountain's  supamit,  —  which  failed  to  happen 
at  Tarawera    in   1885,  although  the  vent  was   closed,  and 


THE  ISLAND   OF  MAUI.  269 

is  not  a  possibility  when  the  vent  is  an  open  one,  —  but 
chiefly  because  a  steep-sided  mountain  is  likely  to  lose  more 
in  height  than  a  broad  lava-cone  from  the  same  amount  of 
undermining. 


II.    ISLANDS    OP   MAUI   AND  OAHU. 

The  subjects  prominently  illustrated  by  the  islands  Maui 
and  Oahu  are  :  the  conditions  of  extinct  volcanoes  in  different 
stages  of  degradation ;  the  origin  of  long  lines  of  precipice 
cutting  deeply  through  the  mountains ;  the  extent  and  condi- 
tion of  one  of  the  largest  of  craters  at  the  period  of  extinc- 
tion ;  and  the  relation  of  cinder  and  tufa  cones  to  the  parent 
volcano. 

A.    ISLAND   OF  MAUI. 

The  accompanying  map  (Plate  XIII.),  reduced  from  the 
recent  large  Government  map/  shows  the  general  features 
of  the   island   of  Maui. 

(1)  The  volcanic  mountain  of  East  Maui,  Haleakala, 
10,032  feet  in  height,  having  at  summit  a  crater  2,500 
feet  in  greatest  depth  and  twenty-three  miles  in  circuit. 

(2)  The  abrupt  depression  of  Kipahulu,  to  the  southeast 
of  the  summit,  surveyed,  but  not  yet  geologically  stud- 
ied, which  looks  as  if  it  were  the  site  of  another  great 
crater. 

(3)  The  slopes  of  eastern  Maui,  little  gullied  by  erosion, 
but  most  so  on  the  side  facing  northeast,  —  the  windward 
side  ;  and  here  the  longest  valleys  scarcely  reaching  to  the 
summit. 

(4)  The  mountain  of  West  Maui,  Eeka,  a  volcano  in  ruins, 

^  On  this  Plate,  as  on  that  of  Hawaii  in  the  "  American  Journal  of  Science  " 
(1888,  vol.  xxxvi.),  most  of  the  lettering  of  the  original  map  is  omitted,  with  neces- 
sarily minor  details  as  to  erosion  and  topography. 


270  VOLCANIC  PHENOMENA 

being  profoundly  cut  up  by  valleys,  and  the  original  height 
reduced  to  5,788  feet  as  the  maximum. 

(5)  The  low  intermont  area  of  Maui,  made  of  the  united 
bases  of  the  two  volcanoes,  but  covered  for  the  most  part 
by  the  lava-flows  of  Haleakala,  whose  fires  continued  in 
action  long  after  the  western  volcano  had  been  turned  over 
dead  to  the  dissecting  elements  ;  the  width  from  north  to 
south  at  the  narrowest  part,  near  the  line  reached  by  the 
lavas  of  Haleakala,  about  six  miles,  and  the  height  at  the 
survey  station  near  its  middle  156  feet. 

In  the  account  which  has  been  given  of  the  volcanoes, 
craters,  and  lava-flows,  as  well  as  the  topography  of  Hawaii, 
it  has  been  apparent  that  the  maps  of  the  Hawaiian  Govern- 
ment Survey  have  been  a  very  prominent  basis  for  the  con- 
clusions presented.  The  Government  map  of  Maui  has  still 
greater  geological  importance  ;  for  Professor  Alexander,  the 
Surveyor-General,  has  made  it,  by  his  accurate  work  and  his 
appreciation  of  the  importance  of  details,  a  contribution  to 
science  of  the  highest  value  and  interest.  What  I  have  to 
say  of  the  extent,  depth,  form,  and  discharge-ways  of  the 
great  crater,  of  the  heights  and  positions  of  cinder-cones,  and 
of  the  erosion  of  the  mountains,  should  be  put  mainly  to  the 
credit  of  the  map,  which  was  Professor  Alexander's  work, 
not  only  in  superintendence  and  geodetic  measurement,  but 
largely  also  in  the  details  of  the  survey.^ 

^  The  author,  moreover,  was  personally  indebted  to  Professor  Alexander's  kind 
providings,  guidance,  and  instructions  for  the  success  of  his  trip  in  1887  (August  4 
to  6)  up  Haleakala  and  into  the  crater,  where  a  night  was  spent,  —  an  exceptionally 
brilliant  night  after  a  day  of  clear  views  from  the  slopes  and  the  summit,  —  and 
also  for  his  excursion  up  Wailuku  valley  on  western  Maui. 

An  excellent  model  of  the  island  of  Maui  has  been  made  by  Prof.  C.  H.  Hitch- 
cock, who  devoted  much  time  to  it  during  his  recent  visit  to  the  Hawaiian  Islands. 
The  Government  map  was  the  chief  source  of  data  for  the  details.  The  vertical 
height  is  increased  three  times,  and  the  craters  and  valleys  are  thus  strongly  brought 
out.  All  such  exaggerated  relief-maps,  whether  of  a  mountain  or  sea-basin,  need 
a  note  of  warning  attached  to  prevent  wrong  conclusions  as  to  slopes  and  heights; 
for  the  ratio  of  three  to  one  changes  a  slope  of  ten  degrees  to  one  of  twenty-seven 
and  a  half  degrees.     Tlie  light  shading  used  on  the  map  of  Hawaii  and  here  on  that 


OF   THE   ISLAND   OF   MAUL  273 


1.  East    Maul 

The  Mountain.  —  The  crater  of  Haleakala  has  been  many 
times  described,  but  first  with  a  detailed  map  in  illustration 
by  Captain  Wilkes.  Captain  Wilkes  states  that  he  is  in- 
debted for  the  map  to  his  artist,  Mr.  Joseph  Drayton ;  ^  and 
considering  that  it  was  from  an  artist's  survey,  not  that  of  a 
surveying  party  with  instruments,  it  is  a  remarkable  piece  of 
work.^ 

The  mountain  is  usually  ascended  from  Paia,  —  a  village 
on  the  north  coast.  The  path,  as  the  map  shows,  passes 
Olinda,  and  reaches  the  edge  of  the  crater  where  the  nearly 
vertical  western  wall  bounding  it  is  not  less  than  twenty-five 
hundred  feet  in  height.  Thence  it  follows  the  summit  south- 
westward  to  the  southwest  angle,  passing  Pendulum  Peak  ^ 
on  the  borders  of  the  crater  just  before  reaching  it.  Here 
are  three  cinder-cones,  and  the  top  of  one  is  the  culminating 
point  of  the  mountain,  10,032  feet  above  tide.  These  sum- 
mit cinder-cones  stand  at  the  head  of  a  long  line  of  similar 
cones  extending  southwestw^ard  down  the  mountain  to  the 
sea ;  and  near  the  sea  at  the  foot  of  the  line  are  three  or  four 
comparatively  recent  lava-streams,  —  enough  to  illustrate  the 
process  of  seashore  extension  by  such  sea-border  outflows. 
At  the  summit,  near  the  southwest  angle  of  the  crater  and 
the  base  of  one  of  the  three  cinder-cones,  a  cinder-made  slope 
of  rather  easy  grade  begins  its  descent  into  the  crater ;  it  is 
the  w^ay  down  ;  on  reaching  the  bottom  the  path  continues 

of  Maui  if;  intended  to  bring  out  the  idea  as  nearly  as  may  be  of  a  mean  slope  of 
seven  to  ten  degrees. 

^  Wilkes's  Narrative,  iv.  255. 

*  The  Expedition  owed  much  to  Mr.  Drayton,  not  only  for  his  excellent  labors 
as  draughtsman  in  all  departments  at  sea,  but  also,  after  his  return,  for  his  manage- 
ment of  engravers,  printers,  etc.,  during  the  publication  of  the  various  Reports. 

'  The  pendulum  station  of  Mr.  E.  D.  Preston,  of  the  Coast  Survey,  in  1887. 
American  Journal  of  Science,  1888,  xxxvi.  305. 

35 


274  VOLCANIC   PHENOMENA 

eastward  to  the  usual  place  of  encampment,  four  and  a  half 
miles  from  the  top. 

Tlie  two  great  DiscJiarge-ioays  of  the  Crater.  —  Besides  its 
lofty  walls  and  great  area,  the  most  remarkable  features  of 
the  crater  are  the  two  openings,  a  northern  and  a  southern, 
a  mile  to  a  mile  and  a  half  wide,  between  precipitous 
walls  of  rock,  —  the  walls  of  the  northern  two  thousand 
feet  and  over,  of  the  southern  one  to  two  thousand  feet, 
—  through  which  poured  the  lava  of  probably  the  last 
of  the  great  eruptions.  The  Kaupo  lava-stream  —  the 
southern  —  has  much  the  smoother  surface,  as  if  more 
recent ;  but  the  broader  Koolau  stream  descended  the  wind- 
ward slope,  and  the  consequent  erosion  may  have  made  all 
the  difference. 

The  Cinder-cones  and  Lavas  at  the  Bottom  of  the  Crater.  — 
Another  striking  feature  of  the  crater  is  the  group  of  red  and 
gray  cinder-cones  which  stand  over  the  bottom,  sixteen  in 
number,  the  highest  nine  hundred  feet  above  its  base,  and 
all  of  them  over  four  hundred  feet,  and  yet  looking  small 
in  the  view  of  the  great  area  from  the  summit.  The  sight 
to  the  northward  when  half-way  to  the  bottom  —  comprising 
the  northern  discharge-way  in  the  distance,  the  highest  of 
the  cinder-cones  in  the  foreground,  and  beyond  these  and  two 
other  cones  the  broad  stream  of  lava  of  the  crater-floor  as 
level  apparently  as  a  river,  stretching  away  between  preci- 
pices of  more  than  two  thousand  feet,  and  then  terminating 
in  an  even  line  at  the  limit  of  vision,  as  if  there  began  the 
plunge  to  the  sea  —  is  wonderfully  like  the  real  river  of  lava 
on  its  downward  way. 

The  cinder-cones  of  the  bottom  were  evidently  the  last 
work  of  the  fires.  The  ashy  surface  of  the  cones  is  without  a 
trace  of  erosion,  and  thus  bears  no  distinct  marks  of  age. 
The  slopes  are  mostly  twenty-five  to  thirty  degrees  and  less, 
and  hence  they  may  have  had  the  pitch  diminished  some- 
what by  the  winds  and  rains  and  earthshocks ;  there  are  no 


OF   THE   ISLAND   OF   MAUI.  275 

channellings  by  descending  waters.  The  material  is  scoria 
in  coarse  fragments  and  sands ;  and  altliougli  in  part  reddish 
and  purplish  originally,  the  red  color  has  generally  been 
deepened  by  oxidation  from  exposure. 

Besides  the  scoria,  there  are  on  some  of  the  cones,  espe- 
cially those  toward  the  borders  of  the  pit,  numerous  large 
blocks  of  gray,  compact,  scarcely  vesiculated  rock.  Some  of 
the  masses  about  a  cone  near  the  place  of  descent  measured 
over  a  hundred  cubic  feet.  The  masses  must  have  been  torn 
off  from  the  throat  of  the  volcano's  conduit,  this  being  the 
only  conceivable  source.  They  indicate  therefore  the  action 
of  vast  projectile  force  at  these  isolated  centres  when  the 
cones  were  in  progress,  and  its  continuation  even  to  the  close 
of  the  ejections ;  and  they  also  are  probable  evidence  of  very 
rapid  work  in  the  cone-making.  A  few  of  the  other  cones 
were  grayish  in  color,  as  if  from  the  abundance  over  their 
slopes  of  these  projected  grayish  stones ;  but  this  supposition 
needs  verification. 

The  cones  stand,  or  appear  to  stand,  on  the  rough,  fresh- 
looking,  scoriaceous  lavas  of  the  bottom,  these  lavas  spread- 
ing away  from  beneath  them.  The  opened  fissures  or  vents 
which  gave  exit  to  the  cinders  first  poured  out  the  lavas ; 
and  then  followed  the  cinder-ejections  as  the  fires  declined  and 
the  liquid  lavas  of  the  vent  became  somewliat  stiffened.  The 
cinder-material  is  proof  of  powerful  projectile  work  ;  for  the 
fragments  of  the  exploding  bubbles  were  thrown  upward,  as 
the  heights  of  the  cones  prove,  many  hundreds  of  feet,  — 
more  than  nine  hundred  to  make  the  highest  cone. 

The  fresh-looking  lava  spreading  away  in  all  directions 
from  the  base  of  the  more  western  of  these  cones  continues 
eastward  throughout  the  crater,  with  little  change  of  fea- 
tures, and  with  the  same  relation  to  the  bases  of  the  several 
cones,  as  if  all  pertained  to  one  epoch  of  eruption,  —  the 
epoch  of  the  last  outbreak  of  Haleakala  ;  the  whole  seems  to 
have  been  the  latest  outflow   of   several   subordinate  vents, 


276  VOLCANIC   PHENOMENA 

after  the  crater  had  made  its   great  discharge  through  tlie 
two  gateways  down  the  mountain. 

This  scoriaceous  lava  of  the  crater  contains  in  many  places 
much  augite  and  chrysolite  in  largish  grains  or  crystals,  be- 
ing both  augitophyric  and  chrysophyric. 

Lavas  of  the  Walls  and  Suinmit.  —  The  lava  of  the  walls_ 
is  in  part  scoriaceous  ;  but  on  the  south  and  southwest  sides 
it  was  commonly  a  very  compact,  rather  light  gray  variety  of 
basalt,  like  that  of  the  projected  blocks  about  some  of  the 
cones.  The  layers  of  compact  basalt  had  often  one  or  more 
parallel  planes  of  fine  or  coarse  vesiculation,  sometimes  at 
intervals  of  one  to  three  or  four  feet.  At  one  locality  on  the 
ascent  of  the  mountain,  the  solid  gray  rock  had  been  found  to 
be  a  convenient  stone  for  stone  implements  of  various  kinds, 
and  a  large  manufacture  was  formerly  carried  on  there  ;  and 
yet  near  by  the  lavas  that  were  so  solid  have  occasional 
planes  of  coarse  vesiculation,  each  one  to  three  or  more 
inches  thick.  Pendulum  Peak,  near  the  summit,  just  north 
of  the  southwest  corner  of  the  crater  (the  place  of  descent), 
consists  largely  of  this  compact  light-gray  basalt,  with  rarely 
any  vesiculation  visible  without  the  aid  of  a  pocket  lens. 

This  compact  basalt  or  doleryte  is  a  common  rock  also 
over  the  lower  slopes  toward  Paia.  It  appears  thus  to  be  to 
a  large  extent  the  material  of  the  older  lavas  while  also 
among  the  recent.  At  the  summit  on  the  west  side,  along  the 
two  miles  passed  over  before  reaching  the  place  of  descent, 
the  compact  variety  of  the  basalt  is  rather  the  exception. 
There  are  large  areas  of  the  same  scoriaceous  lava  that  covers 
the  bottom  of  the  crater,  and  in  some  places  it  is  equally 
augitophyric  and  chrysophyric,  the  augite  in  well-defined 
crystals.  One  of  these  areas  is  just  north  of  Pendulum  Peak ; 
and  a  large  region  on  the  west  border  of  the  crater  looks  as 
if  successive  streams  of  lava  had  recently  flowed  one  over 
another,  piling  up  layer  on  layer,  so  that  by  this  means  the 
surface  for  a  breadth  of  a  mile  or  more  westward  from  the 


OF   THE   LSLAND   OF    MAUI.  277 

summit  line  had  derived  its  unusual  steepness  of  15°  to  16°. 
The  lava-streams  of  the  surface  have  the  appearance  of  being 
overflows  from  the  crater,  —  as  if  the  great  pit  had  been 
full  to  the  brim  before  the  outbreak,  and  had  poured  out  from 
time  to  time  small  streams  like  those  of  a  full  lava-lake  in 
Kilauea.  But  they  more  probably  came  from  fissures  cut 
throug;h  to  the  summit  at  the  time  of  the  last  or  some  one 
of  the  later  eruptions. 

The  fact  that  lavas  of  the  summit  are  so  very  chrysolitic, 
even  at  a  height  of  nearly  ten  thousand  feet,  has  an  impor- 
tant bearing  on  the  question  as  to  the  effect  of  high  specific 
gravity  in  determining  the  distribution  of  materials  in  liquid 
lavas. 

Crystals  of  augite  and  large  grains  of  chrysolite  are  com- 
mon in  the  loose  material  at  the  base  of  the  cinder-cones  at 
the  summit,  near  the  place  of  descent,  and  colored  glassy 
crystals  of  labradorite  occur  with  them.  These  summit  cones 
have  the  recent  appearance  and  other  features  of  those  over 
the  crater's  bottom,  and  appear  to  be  of  the  same  series  and 
time  of  origin ;  and  the  cinder-made  slope  into  the  crater  on 
that  side  was  probably  made  in  part  from  the  ejections  of 
these  summit  cones. 

The  prohable  Nature  of  the  last  Eruption.  —  The  great  dis- 
charge-ways of  Haleakala,  one  to  one  and  a  half  miles  wide, 
with  the  walled  valleys  confining  them,  look  as  if  the  results 
of  enormous  rents  of  the  mountain,  made  when  the  mountain 
emptied  itself  by  the  wide  channels.  But  they  may  have 
been  in  existence  Ijefore,  and  have  been  simply  used  for 
the  last  of  the  outflows.  They  are,  nevertheless,  evidence 
of  rents  at  some  time,  and  of  a  vast  amount  of  removal  of 
material  in  some  way,  —  by  subsidence  or  otherwise.  The 
height  of  the  walls  at  the  gaps  —  two  thousand  feet  and 
over  at  the  Koolau  gap,  and  a  thousand  feet  and  over  at  the 
Kaupo  —  is  a  minimum  measure  of  the  amount  of  material 
removed.     In  my  "  Exploring  Expedition  Report  "  I  sugs^est 


278  VOLCANIC   PHENOMENA 

that  the  mountain  was  fissured  across  along  the  lines  of  the 
two  discharge-ways,  and  the  eastern  block  shoved  off  a  mile 
or  two.  But  a  subsidence  of  the  masses  that  occupied  them 
into  caverns  below,  leaving  the  walls  as  fault  planes,  may  be 
more  probable.  The  abyss  which  received  them  in  this  case 
had  been  prepared  during  a  long  period  of  undermining 
through  ejections.  Still  there  is  some  reason  to  believe  in 
the  grander  view  of  a  subsidence  of  the  wdiole  eastern  block, 
after  the  cross-fracturing.  The  island,  as  is  seen  on  the  map, 
is  abruptly  narrowed  (instead  of  widened)  at  the  spots  where 
the  Koolau  and  Kaupo  streams  reach  the  sea  ;  and  the  part 
to  the  eastward  is  small,  as  if  narrowed  by  such  a  subsidence. 
Moreover,  the  mean  height  of  the  eastern  crater-wall  is  lower 
than  that  of  the  opposite  or  western  by  five  hundred  to  a 
thousand  feet.  A  subsidence  of  a  thousand  feet  increasing  in 
amount  to  the  eastward  would  account  for  the  narrowing  and 
for  the  very  short  eastern  radius  of  the  eccentric  volcano. 
The  question   merits  investigation. 

The  evidence  that  the  lavas  were  discharged  in  both  direc- 
tions at  once  at  the  last  eruption  consists  in  the  nearly  uni- 
form appearance  of  the  fresh  lavas  over  the  bottom  of  the 
crater  from  one  end  to  the  other,  and  their  continuing  into 
and  apparently  behig  the  streams  that  descend  the  Kaupo 
and  Koolau  discharge-ways.-  Mr.  J.  M.  Alexander  has  re- 
marked that  the  crater  is  probably  a  double  one,  a  combina- 
tion of  two  great  craters,  as  Mokuaweoweo  at  the  summit  of 
Mount  Loa  is  compound  in  structure.  This  is  no  doubt  his- 
torically true  ;  but  at  the  latest  of  the  eruptions  there  was 
probably  one  action  over  the  whole,  the  distinction  for  the 
time  obliterated. 

The  period  of  the  last  summit  eruption  is  unknown.  Mr. 
Bailey,  of  Wailuku,  Maui,  has  stated  that,  according  to  an 
island  tradition,  a  lateral  eruption  of  the  mountain  occurred 
about  one  hundred  and  fifty  years  since  in  the  district 
of    Honuaaula  of    the  southern  part   of   East    Maui,  at   an 


OF   THE   ISLAND   OF   MAUI.  279 

estimated  elevation  above  the  sea  of  about  four  hundred 
feet. 

Activity  of  the  Crater  ending  in  Cinder-ejections.  —  The 
origin  of  the  crater  of  Haleakala  needs  no  explanation  be- 
yond that  given  in  the  remarks  on  page  149,  on  the  origin 
of  craters  generally. 

Haleakala  is  an  example  of  a  basaltic  volcano  which 
reached  its  end,  through  declining  fires,  in  cinder-ejections  ; 
but  it  left  its  great  crater  open,  and  two  thousand  to 
twenty-five  hundred  feet  deep,  with  the  greater  part  of  the 
bottom  free  from  the  cinders  notwithstanding  the  amount  dis- 
charged. The  latest  down-plunge  or  subsidence,  by  which  the 
vast  pit  and  perhaj)s  also  its  discharge-ways  were  made,  may 
therefore  have  filled  full  the  empty  subterranean  chambers 
that  former  outflows  had  produced,  and  left  the  mountain 
solid  instead  of  hollow.  Mount  Kea  on  Hawaii,  13,805  feet 
in  height,  also  ended  its  work  with  cinder-eruptions  ;  but  the 
ejected  material  of  lavas  and  cinders  obliterated  so  far  the 
old  crater  that  no  visitor  of  the  region  has  yet  found  traces 
of  its  former  limits.  Whether  Mount  Kea  is  a  hollow  moun- 
tain or  not  remains  to  be  ascertained. 

After  the  above  was  written,  the  results  of  the  pendulum 
investigations  of  Mr.  E.  D.  Preston  at  the  summit  of  Hale- 
akala were  made  known  in  a  paper  published  in  November, 
1888,^  and  they  have  afforded  unexpected  evidence  on  these 
doubtful  points.  They  led  him  to  the  important  conclusion 
that  "  the  density  of  the  mountain  is  at  least  equal  to  its  sur- 
face density,"  and  that  therefore,  unlike  some  results  obtained 
on  the  continents,  "it  is  a  solid  mountain,"  so  that  tlie  inte- 
rior must  have  been  left  filled  by  the  subsidence  of  rock  that 
made  the  great  crater  at  the  summit.  He  states  also  that  "  the 
zenith  telescope  observations  at  the  foot  of  the  mountain  in- 
dicate the  same  fact." 

^  "  On  the  Deflection  of  the  Plumb-line  and  Variations  in  Gravity  in  the  Hawaiian 
Islands,"  American  Journal  of  Science,  1888,  xxxvi.  305. 


280  VOLCANIC   PHENOMENA 

Mr.  Preston  states  further  that  at  Kohala,  on  the  noi^tli 
coast  of  the  island  of  Hawaii,  the  pkimb-line  deflections  were 
half  a  minute  southward,  which,  he  adds,  is  well  explained 
by  the  position  to  the  southward  of  all  the  great  mountains 
of  Hawaii.  He  records  also  that  at  Hilo,  on  the  cast  coast,  the 
deflection  was  a  fourth  of  a  minute  to  the  northivard.  Mr. 
Preston  remarks  that  "  there  is  no  explanation  "  of  this  re- 
sult at  Hilo  "  miless  we  assume  that  the  south  side  of  Ha- 
waii, where  the  volcanoes  are  active,  is  much  less  dense 
than  the  north  side,  where  the  fires  have  been  slumbering  for 
centuries."  But  to  the  north  of  Hilo  is  a  long  reach  of  ocean, 
the  coast  of  Hawaii  there  trending  northwest ;  the  summit  of 
Mount  Kea,  13,805  feet  high,  is  twenty-five  miles  distant  and 
bears  N.  75°  W. ;  and  that  of  Mount  Loa,  13,675  feet  high, 
is  thirty-five  miles  distant  and  bears  S.  63"  W.  ;  and  the  cen- 
tre of  gravity  of  the  combined  mass  (the  lowest  level  over  fiv& 
thousand  feet)  bears  probably  a  little  south  of  due  west.  It 
appears,  hence,  that  we  have  here  evidence  that  Kea  is  like 
Loa,  not  solid ;  that  it  is  a  hollow  mountain,  as  inferred 
above  from  the  absence  of  a  summit  crater  ;  but  Mr.  Preston 
is  probably  right  in  his  inference  that  Mount  Loa  is  the  more 
cavernous  of  the  two.  Additional  plumb-line  and  pendulum 
observations  are,  however,  much  to  be  desired. 

2.    West   Maui. 

West  Maui  has  lost  the  original  slopes  of  its  great  cone 
and  its  crater  through  erosion.  It  has  been  supposed  that 
remains  of  three  great  craters  may  be  distinguished  in  the 
mountains :  the  largest  at  the  head  of  Wailuku  or  lao  valley, 
on  the  north  border  of  which  rises  the  highest  peak,  Puu 
Kukui,  5,788  feet  high  ;  another  in  the  less  deep  valley  of 
Waihee,  just  north  of  this  ;  and  a  third  at  the  head  of  the 
Olowaiu  valley,  to  the  south. 

The  author  has  examined  only  the   Wailuku  valley,  the 


OF  THE   ISLAND   OF  MAUI.  281 

largest  of  the  three,  —  so  named  from  the  village  on  the 
coast  near  its  entrance.  The  valley  is  a  deep  cut  into  the 
mountains,  remarkably  grand  in  its  precipitous  walls  with 
their  thin-crested  summits.  It  widens  somewhat  toward  its 
head,  and  in  tiiis  upper  part  an  extensive  plateau  occupies 
the  centre.  The  torrent  of  the  valley  is  here  divided  be- 
tween two  tributaries,  one  running  either  side  of  the  plateau. 
The  height  and  rather  bold  sides  of  the  plateau  at  the  head 
of  the  valley,  and  its  size  and  position,  taken  in  connection 
with  its  location  near  the  centre  of  the  mountain  range,  ap- 
pear to  make  it  pretty  certain  that  the  plateau  represents 
the  floor,  or  rather  what  is  left  of  the  central  area,  of  the 
great  crater. 

As  to  the  former  crater-condition  of  the  other  two  valleys 
mentioned,  nothing  is  known.  The  idea  of  their  having  been 
craters  is  based  on  the  size,  depth,  and  boldness  of  the  walls 
and  the  amphitheatre-like  head.  But  these  features  are  com- 
mon results  of  denudation  in  old  volcanic  islands,  and  there- 
fore, in  the  question  here  considered,  have  alone  little  weight. 

3.   The   Eccenteic   Form   of   the   Maui   Volcanoes. 

The  map  of  Maui  illustrates  a  Hawaiian  feature  of  volcanic 
mountains  which  may  be  common  in  other  regions.  The  chief 
crater  of  the  mountain  is  not  at  its  centre.  In  Haleakala  the 
ratio  of  the  radii  east  and  west  of  the  crater  is  2  :  3  ;  and  in 
West  Maui,  8:  11.  The  shorter  radius  is  to  the  south-south- 
east of  the  crater  in  one  and  to  the  southeast  in  the  other. 

In  Hawaii  it  is  not  easy  to  mark  off  the  true  base  of  Mount 
Loa.  But  we  have  the  fact  that  in  both  the  summit  crater 
and  Kilauea  the  form  is  oblong,  and  each  has  its  intenser  ac- 
tivity in  the  more  southern  portion,  —  the  south-southwestern 
in  one,  and  the  southwestern  in  the  other.  The  effect  is  not 
due  to  the  winds,  for  the  mountains  consist  almost  solely  of 

lava-streams. 

36 


282  VOLCANIC  PHENOMENA 


4.   Consolidated   Drift-sand   Ridge. 

The  positions  of  the  high  ridge  of  coiisoHdated  coral-sand 
of  Wailuku  are  indicated  on  the  map.  Whether  it  is  a  proof 
of  elevation  or  not  is  yet  undecided.  The  sands  are  at  the 
present  time  drifted  by  the  trade-winds  to  the  farther  inland 
limit  of  these  ridges  and  over  their  surfaces,  —  a  fact  which 
seems  to  show  that  present  conditions  are  sufficient  for  their 
production. 


B.     ISLAND    OF   OAHU. 

From  the  map  of  Oaliu  (Plate  XIV.)  it  is  apparent  that  in 
the  first  place  the  island  consists  of  two  eroded  mountain 
regions,  an  eastern  and  a  western,  separated  by  a  plain 
sloping  gently  downward  to  the  opposite  coasts  and  upward 
toward  the  eastern  mountains.  A  more  remarkable  feature, 
secondly,  is  the  long  and  high  precipice  of  the  eastern  moun- 
tains, fronting  northeastward,  and  thus  facing  the  trade- 
winds.  Besides  these  characteristics,  there  are  lateral  or 
subordinate  volcanic  cones  on  the  sea-border,  of  which 
Diamond  Head,  Pmichbowl,  and  the  Koko  Head  craters  on 
the  eastern  cape  (Plate  XIV.,  Figs.  1,  2,  3)  are  examples. 
Further  the  island  is  the  only  one  of  the  group  that  has  a 
nearly  continuous  coral-reef  fringing  the  shores.  It  owes  to 
this  reef  the  harbor  of  Honolulu,  the  one  good  harbor  of 
the  group,  and  also  the  jDOssibility  of  a  much  larger  and  better 
one  at  Pearl  River,  seven  miles  west  of  Honolulu ;  the  cutting 
of  a  channel  through  the  reef  is  all  that  is  needed,  as  has  long 
been  recognized,  to  make  these  capacious  inner  waters  avail- 
able for  shipping.^     Another  interesting  feature  (e)   is  the 

1  Honolulu,  the  capital  of  the  Hawaiian  Kingdom,  was  a  collection  of  thateherl 
huts  in  1840,  with  exceptions  only  in  a  custom-house,  an  unfinished  coral-rock 
church,  and  a  few  dwellings  of  civilized  aspect.    To-day  it  is  city-like  in  its  houses  j 


Plate  XIV. 


^KokoHeaa 


]w~2E 


Fisr.  1.  The  volcanic  cones:  o,  Diamonrl  Heafl,  or  Leahi ;  h,  Kaimuki,  or  Telegraph 
Hill;  c.  Maaumae.  2.  Punchbowl. or  Priowaina;  with  Nunanu  valley  to  the  left,  and  the 
peaks  Konahuanui  and  Lunahili,  right  and  left  of  the  pali.     3.  The  Koko  Head  craters. 


OF    THE   ISLAND   OF   OAHU.  285 

existence  of  an  elevated  coral-reef  on  the  borders  of  the 
island,  having  its  inner  limits  approximately  indicated  on 
the  map  by  a  dotted  line. 

The  facts  on  which  the  following  acconnt  of  the  island  is 
based  and  the  views  deduced  from  them  are  for  the  most  part 
contained  in  the  author's  "  Expedition  Geological  Report." 
The  accompanying  map  (Plate  XIV.)  differs  little,  excepting 
in  improvement  in  outline  and  topography,  from  the  colored 
geological  map  of  the  "  Report,"  and  the  outline  of  the  ele- 
vated coral-reef  and  its  coral-rock  and  sand-bluff's  are  copied 
from  it.^  The  views  of  the  tufa-cones  on  the  same  plate  are 
simply  new  drawings  from  some  of  the  author's  old  sketches. 
Fuller  particulars  and  some  views  not  reproduced  will  be 
found  in  the  •'  Report."  Another  excursion  around  a  large 
part  of  the  island,  taken  with  President  Merritt  in  1887, 
refreshed  old  memories  and  added  new  facts. 

1.    Featukes,  Structure,  and  Origin  of  Oahu. 

General  Features ;  Contrast  with  the  Island  of  Maui.  — 
Like  Maui,  Oahu  is  in  origin  a  volcano-doublet,  —  that  is,  as 
regards  rock-structure,  it  was  the  united  work  of  two  great 
volcanoes,  a  western  and  an  eastern.  But,  unlike  Maui,  its 
two  volcanic  cones  or  domes  have  suffered  so  great  loss  that 
the  position  of  either  crater  is  wholly  a  matter  of  conjecture. 

A  large  part  of  the  loss  Oahu  has  suffered  is  due  to  denud- 
ing agencies.  East  Maui,  as  the  map  on  Plate  XIII.  illus- 
trates, has  lost  in  this  way  comparatively  little  of  its  original 

its  streets  electrically  lighted,  its  public  squares,  large  hospital  grounds,  spacious 
government  buildings,  —  among  them  a  palace  good  enough  for  any  potentate,  — 
and  its  excellent  hotel  ;  and  through  the  addition  of  groves  and  avenues  of  intro- 
duced palms  and  tropical  trees  (some  of  which  are  always  in  flower  or  fruit),  it  is 
fast  becoming  a  place  of  ideal  beauty.  Honolulu  is  the  centre  of  all  the  island 
activities,  including  inter-island  navigation. 

^  The  map  of  Oahu  on  Plate  XIV.  is  reduced  from  the  Hawaiian  Government 
chart  of  1881,  made  after  a  survey  by  Sereno  E.  Bishop,  Assistant  in  the  Topo- 
graphical work. 


286  VOLCANIC   PHENOMENA 

evenness  of  surface,  owing  to  the  recency  of  its  extinction. 
Its  windward  gorges  are  narrow,  and  only  shallow  gulches 
occur  over  the  leeward  surface.  The  ratio  of  its  diameters 
at  base,  1 : 1-3,  is  probably  very  near  the  original  ratio.  West 
Maui  is  profoundly  gorged  on  all  sides  and  most  deeply  so  to 
windward,  illustrating  results  of  longer  wear  than  East  Maui 
has  had.  But  something  of  the  old  slopes  remain,  and  in  the 
base  we  have  still  the  ratio  of  its  old  diameters,  1  :  1*4,  with 
the  outline  little  indented.  The  double  lesson  is  taught :  (1) 
what  denudation  from  descending  waters  does  to  a  volcanic 
cone  5°  to  10°  in  slope  in  the  region  of  the  trades  ;  (2)  what, 
on  the  contrary,  the  sea  cannot  do,  no  encroachments  of  note 
existing  to  attest  to  its  powei",  notwithstanding  the  length  of 
the  era  of  denudation. 

Oahu  resembles  Maui  in  having  the  western  mountain-cone 
the  most  time-worn  and  the  smaller  in  area,  but  here  the  like- 
ness ends.  Both  of  its  mountains  are  deeply  eroded.  Further, 
only  a  section  of  the  East  Oahu  cone  now  exists.  The  slopes 
of  its  southern,  western,  and  northwestern  sides  remain  ;  Imt 
the  northeastern  are  cut  off  by  a  great  precipice,  twenty  miles 
long,  which  is  made  for  the  most  part  of  the  edges  of  the 
lava-streams  that  slope  southward  and  westward.  The  sharp- 
edged  serrated  ridge,  making  the  summit  of  the  precipice,  is 
from  one  to  three  thousand  feet  in  height,  and  at  its  north- 
eastern base,  from  Kualoa  eastward,  there  is  in  general  only 
a  narrow  strip  of  land  with  low  hills,  the  width  but  three 
or  four  miles  except  in  the  Kaneohe  peninsula.  The  preci- 
pice continues  beyond  Kualoa  northwestward,  but  not  the 
low  land  at  its  base. 

These  features  have  occasioned  peculiarities  in  the  results 
of  denudation  on  East  Oahu.  The  leeward,  or  the  southern, 
side  of  the  island  has  long  and  deep  valleys.  Some  of  them 
head  in  broad  amphitheatres  under  the  crested  mountain. 
But  the  broadest,  the  Nuuanu  Valley,  behind  the  city  of 
Honolulu  (see  the  map  and  left  part  of  Fig.  2),  has  a  gradual 


OF   THE   ISLAND   OF   OAHU.  287 

ascent  for  six  miles  to  the  top  of  the  precipice,  or  "  pali,"  as 
it  is  ordinarily  called,  where  it  overlooks  the  northeastern 
sea-border  plains  and  hills.  The  height  of  the  "  pali "  is 
only  1,207  feet  above  the  sea  ;  but  on  either  side  are  the 
highest  peaks  of  the  range,  Konahuanui  3,105  feet  in  height, 
and  Lanihuli,  2,775  feet.  In  the  sketch  (Fig.  2)  the  peak 
to  the  right  of  the  valley  is  Konahuanui. 

On  the  contrary,  the  ivindward  side  of  the  island,  along 
the  twenty-mile  precipice,  has  buttresses  and  shallow  alcoves, 
with  a  buttress  here  and  there  lengthened  out  into  a  ridge  ; 
and  only  farther  northward,  near  Kualoa  and  beyond,  are 
there  the  longer  valleys  or  gorges  and  ridges,  characteristic  of 
deeply  worn  windward  slopes.  But  along  the  whole  range 
of  the  precipice  and  beyond,  there  is  wonderful  grandeur  in 
the  scenery.  Bare  rock  might  be  expected  in  the  lofty  preci- 
pices and  sharply  cut  or  rounded  alcoves,  as  in  Colorado. 
But,  instead,  the  steepest  walls  are  green  ;  and  rocks  are 
seen  only  here  and  there  through  the  dark  and  dense  foliage. 
The  mountain  back  from  the  coast  near  Kualoa  Point,  twelve 
to  fifteen  hundred  feet  high,  is  one  of  the  most  remarkable 
of  the  architectural  clusters  of  northeastern  Oahu.  It  stands 
isolated,  like  a  buttressed  temple  cut  from  the  rocks  ;  and  one 
is  led  almost  unconsciously  to  look  for  an  entrance  to  the 
solemn  grandeur  of  its  interior. 

Near  Punaluu,  a  few  miles  farther  to  the  northeast,  a  nar- 
row gorge,  called  Kaliuwaa,  has  become  a  place  of  much  re- 
sort on  account  of  its  narrow  shaded  recesses,  its  lofty  walls, 
and  the  cascade  that  pours  down  the  mountain  trench  at  its 
head ;  but  also  for  an  almost  cylindrical,  smooth-sided  shaft, 
thirty  and  forty  feet  in  its  diameters,  which  extends  up  ver- 
tically for  at  least  three  hundred  feet.  It  is  called  by  the 
natives  ''•  the  canoe,"  the  shape  being  nearly  that  of  the  body 
of  a  canoe  standing  on  end.  The  lavas  are  light  gray  basalt, 
in  layers  as  usual  ;  but  the  surface  is  smooth,  even  over  the 
junctions  of  the  layers.     Thoughts  of  falling  water,  of  a  local 


288  VOLCANIC   PHENOMENA 

lava-conduit,  of  chiselling  natives,  come  up  when  before  it ; 
but  the  question,  How  ?  remains  without  a  positive  answer. 

The  many  narrow  gorges  of  this  part  of  Oahu,  richly 
draped  in  ferns  and  shrubbery,  with  streams  begun  in  cas- 
cades and  continued  in  dashing  torrents,  offer  any  number  of 
tempting  excursions.  But  the  road  down  the  ''  pali "  on  the 
way,  while  good  enough  for  the  active  pedestrian,  as  in  1840, 
is  for  a  horse  and  carriage  only  a  breakneck  way,  impassable 
except  as  the  horse  is  detached  and  led,  and  the  carriage  is 
held  back  with  all  available  strength  lest  it  take  its  own 
course  down.  The  author  had  the  best  of  it  in  1887,  for 
he  took  charge  of  the  horse ;  but  President  Merritt  had 
grave  conflicts  with  the  vehicle,  though  safe  down  at  last. 

Orograjjhic  Condition  of  East  Oahu.  —  From  the  facts 
mentioned,  it  appears  to  be  plain  that  the  chief  structural 
difference  between  East  Oahu  and  East  Maui  is  that  the 
latter  is  a  whole  volcanic  mountain,  and  the  former  a  piece 
of  one.  By  some  means  the  Oahu  mountain-cone  or  dome 
has  lost  a  large  piece  from  its  mass,  —  all  that  once  existed 
northeast  of  the  twenty-mile  precipice.  The  size  of  the  lost 
piece  it  is  not  easy  to  determine.  The  lava-streams  of  the 
leeward  slopes,  which  dip  away  from  the  precipice  mostly 
at  an  angle  of  3°  to  5°  (as  seen  in  the  intersecting  valleys), 
must  have  come  from  some  point  or  points  beyond  it  to 
the  northeastward. 

Following  the  leeward  slopes  around  westward  and  north- 
ward, we  find  all  of  them  pointing  upward  toward  the  higlier 
part  of  the  mountains,  as  if  the  source  were  somewhere  in 
that  direction.  But  just  where  remains  in  doubt ;  and  it  is 
questioned  whether  there  may  not  have  been  two  or  more 
great  craters  along  the  line. 

No  point  or  region  has  a  more  reasonable  claim  for  con- 
sideration in  this  respect  than  the  head  of  Nuuanu  valley. 
In  situation  and  width,  and  the  features  at  its  head,  it  is  just 
what  should   be  looked  for  in  a  great  discharge-way.      The 


OF   THE   ISLAND   OF   OAHU.  289 

dip  of  the  bods  diminishes  from  3°  to  1°  toward  the  top,  and 
at  the  "  pali  "  the  beds  were  very  nearly  or  quite  horizontal. 
This  is  favorable  to  the  conclusion  that  the  crater  was  either 
at  the  head  of  the  valley  or  near  by  it,  just  beyond  the 
precipice.  The  low  land  below  over  the  Kaneohe  peninsula, 
and  between  this  peninsula  and  the  ''  pali,"  is  a  region  of 
tufa-hills  and  other  small  cones,  unlike  any  part  elsewhere 
of  the  north  or  northeast  coast.  In  addition,  at  the  head  of 
Nuuanu  valley,  very  near  the  top  of  the  "  pali,"  there  are 
the  remains  of  a  red  cinder-cone.  Besides  this,  on  descend- 
ing the  steep  "  pali "  by  the  path,  there  is  to  the  east  of  the 
path  a  long  broad  slope,  35°  to  40°  in  angle,  consisting  of 
reddish  layers  of  volcanic  cinders,  scoria,  earth,  and  stones,  — 
indicating  cinder-ejection  from  some  point  above,  looking  in 
1887  very  much  as  it  did  in  1840. 

It  is,  therefore,  most  probable  that  the  centre  of  volcanic 
activity  for  East  Oahu  was  in  the  vicinity  of  the  "  pali," 
above  the  low  region  a  little  to  the  northeast  of  it,  The 
cinder-cones  above  mentioned  may  have  been  results  of  the 
last  efforts  of  the  declining  fires,  like  those  of  Haleakala  and 
Mount  Kea. 

In  1840  the  author  was  led  to  locate  the  central  crater  on 
the  Kaneohe  peninsula,  the  head  of  the  "  pali "  seeming  to  be 
too  near  the  southern  foot  of  the  mountain.  But  the  fact 
that  the  volcanic  mountains  of  East  and  West  Maui  are 
eccentric  in  ground-plan,  and  that  the  same  feature  quite 
certainly  characterized  this  Oaliu  cone,  makes  the  position 
near  the  "  pali  "  the  most  probable.  In  Haleakala  the  centre 
of  the  crater  is  only  six  miles  from  the  southern  shore  ;  and 
this  distance  in  the  Oahu  crater,  on  the  above  supposition, 
would  be  about  seven  miles.  The  idea  of  an  eccentric  cone 
fourteen  or  fifteen  miles  in  the  transverse  diameter  through 
the  crater  is  thus  strongly  favored.  On  further  comparison 
with  Haleakala,  it  is  found  that  the  part  of  the  longer  diam- 
eter of  the  mountains  which  lies  northwest  of  the  centre  of 

37 


290  VOLCANIC   PHENOMENA 

the  crater  is  about  nineteen  miles  in  length  on  Maui,  and  on 
Oahu  it  would  be  nearly  twenty-five  miles.  The  small  dip 
of  1°  to  3°  prevails  widely  about  the  mountains  at  Kualoa 
point  and  to  the  northward,  as  well  as  in  the  upper  part  of 
the  Manoa  valley,  w^est  of  the  Nuuanu ;  and  from  this  it  may 
be  inferred  that  the  East  Oahu  mountain  was  a  dome,  like 
Mount  Loa,  rather  than  a  cone  like  Mount  Kea.  The  exist- 
ence of  one  or  more  craters  west  of  the  ^'  pali "  has  been 
urged,  and  is  possible ;  but  no  special  facts  that  sustain 
this  view  have  become  known.  The  amphitheatre  at  the 
head  of  Manoa  valley  is  referred  to  by  Mr.  Brigham  as  prob- 
ably the  site  of  a  crater ;  but  it  may  be  only  an  amphitheatre 
of  erosion. 

Ori(jin  of  the  Long  Preciioice  on  Oahu.  —  The  long  precipice 
of  East  Oahu  has  been  attributed  to  erosion.  But  there  is 
no  good  evidence  that  such  transverse  walls  are  legitimate 
effects  of  erosion,  either  fluvial  or  marine.  As  illustrated  on 
Maui  (p.  286),  the  sea  works  with  extreme  slowness  in  bat- 
tering; lava-cliffs,  and  cannot  work  at  all  below  the  limit  of 
forceful  wave-action,  —  a  level  not  twenty  feet  beneath  the 
sea-level.  Fluvial  action  makes  long  valleys  in  the  long  de- 
scending mountains,  and  has  done  grand  work  in  alcoving 
the  long  precipice,  and  carving  battlements  and  temples  out 
of  the  rocky  piles  that  were  left,  as  is  well  exhibited  in  the 
Kualoa  bluffs,  while  the  sea  has  not  even  scraped  away  the 
small  tufa-cones  on  its  borders.  It  might  be  said  that 
the  cones  of  Kaneohe  and  the  ''  pali "  have  been  made  since 
the  era  of  erosion  ;  but  this  disconnects  their  origin  by  a 
very  long  era  from  the  period  of  activity  in  the  crater. 

Another  view  with  regard  to  the  origin  of  the  precipice  is 
presented  by  the  author  in  his  "Exploring  Expedition  Re- 
port;" namely,  that  it  was  made  by  a  profound  fracturing  of 
the  mountain  dome  across  from  southeast  to  northwest,  and 
a  drop-down  of  part  of  the  outer  or  eastern  section.  The  line 
of  fracture  was  irregular,  —  the  course  rather  of  a  series  of 


OF   THE   ISLAND   OF  OAHU.  291 

fractures  ;  and  subsidences  of  varying  extent  may  have  taken 
place  along  the  line,  becoming  smaller  to  the  northwest,  where 
high  ridges  are  left  between  the  precipice  and  the  coast. 
The  amount  of  displacement  was  not  less  than  the  heidit 
of  Konahuanui,  3,105  feet,  and  probably  it  nuich  exceeded 
this. 

Great  catastrophic  subsidences  are  not  uncommon  in  vol- 
canic regions.  In  the  account  of  Maui  and  its  crater  the  fact 
of  a  subsidence  not  less  than  twenty-five  hundred  feet,  accom- 
panying and  following  some  one  of  its  eruptions,  appears  to 
be  placed  beyond  doubt.  Hawaii  has  plain  evidences  about 
its  crater  of  subsidences  hundreds  of  feet  in  amount  of  dis- 
placement, if  not  thousands ;  and  there  are  high  precipices, 
like  that  at  Kealakekua  Bay,  for  which  there  appears  to  be 
no  other  probable  origin. 

The  small  western  island  of  the  Hawaiian  .g;roup,  Niihau, 
has  a  bold  precipice  as  its  eastern  face,  fifteen  to  eighteen  hun- 
dred feet  in  height  above  the  sea,  and  the  lava-streams  of 
the  island  pitch  from  the  precipice  to  the  westward,  showing 
that  the  streams  flowed  from  a  point  to  the  eastward,  and 
that  a  large  piece,  perhaps  the  larger  part,  of  an  old  volcano 
has  disappeared.     Kauai,  north  of  Niihau,  has  its  Napali  cliff, 
a  dozen  miles  long,  along  its  southwest  side,  in  a  line  with 
the  Niihau  cliff.     Molokai,  to  the  east  of  Oahu,  was  once,  as 
its  lava-streams  prove,  a  doublet  of  volcanoes,  like  Maui ;  but 
it  has  been  shaved  down  to  a  strip  of  land  thirty-five  miles 
long,  and  not  a  fifth  of  this  in  mean  width.     The  eastern  part 
has  an  alcoved  precipice  facing  the  north,  which  rises  to  a 
height  of  twenty-five  hundred  feet  above   the  sea.     It  en- 
closes a  strip  of  land  along  the  seashore ;   and  on  this  spot, 
thus  walled  in,  it  has  been  found  convenient  to  locate  the 
Leper  quarantine-ground   of    the  islands.     Lanai,   a  narrow 
island  south  of  Molokai,  about  twentv  miles  Ions;,  has  a  bold 
front  to  the   south   and  gradual  slopes  from  it  in  other  di- 
rections.    Thus  such  precipices  are  rather  the  rule   in   the 


292  VOLCANIC  PHENOMENA 

Hawaiian  group  ;  and  if  seashore  erosion  is  not  the  origin, 
—  as  many  facts  from  tlie  islands  of  the  Pacific  appear  to 
show,  —  fractures  and  subsidence  must  be. 

A  great  volcano  is  a  disgorger  of  lava  in  vast  floods,  and 
so  it  makes  its  mountain ;  and  it  may  also  make  empty 
cavities  at  the  same  time  and  as  a  consequence.  As  long  as 
the  ascensive  force  keeps  the  liquid  lava-column  of  the  active 
volcano  fully  up  to  the  summit  crater,  the  mountain  may 
have  only  local  cavities.  But  whenever  a  great  discharge 
takes  place,  a  coequal  cavity  may  result ;  and  if  the  dis- 
charge is  from  fissures  at  the  base  of  the  cone  fifteen  to 
eighteen  thousand  feet  below  the  sea-level  (not  a  greater 
depth  than  exists  in  the  neighboring  seas)  an  enormous 
cavity  may  be  left,  which  only  the  renewed  action  of  the 
ascensive  force  would  fill.  If  the  mountain  then  became  ex- 
tinct, with  no  return  of  the  liquid,  it  would  be  a  hollow 
mountain  ;  and  the  greatest  of  subsidences  which  the  Ha- 
waiian facts  seem  to  indicate,  are  small  compared  with  the 
possible  consequences  of  such  a  condition. 

2.  Tufa  and  other  Lateral  Cones  of  East  Oahu. 

Several  of  the  tufa-cones  of  Oahu  are  represented,  as 
already  stated,   on  Plate  XIV. 

Punchbowl  (Fig.  2)  stands  on  the  northern  border  of  Hono- 
lulu (at  P  on  the  map).^  Its  highest  point  is  498  feet  above 
tide-level.  The  tufa  of  the  beds  constituting  it,  though  rather 
feebly  consolidated,  is  quarried  on  the  west  side  of  the  cone, 
and  specimens  may  there  be  conveniently  obtained.  It  is  a 
yellow  to  brown,  in  part  resin-lustered,  palagonite-like  rock, 
bearing  evidence,  in  its  constitution  and  in  the  dip  of  the 
beds,  that  mud-making  warm  waters  were  concerned  in  the 
deposition  ;  and  the  brown,  in  place  of  red,  color  is  probable 

1  The  sketch  was  taken  in  1840  from  the  deck  of  the  ship  "  Peacock"  as  she  lay- 
in  the  harbor.     The  native  huts  at  its  foot  are  omitted. 


OF   THE  ISLAND   OF   OAHU.  293 

• 

evidence  that  the  temperature  of  the  water  was  below  200°  F. 
Punchbowl  —  Puowaina  of  tlie  natives  —  has  recently  been 
converted  into  a  Park. 

Diamond  Hill  (Fig.  1)  makes  the  prominent  cape  east  of 
the  city  ;  its  bold  southern  brow  has  a  height  of  761  feet 
above  the  sea  at  its  base.  It  is,  like  Punchbowl,  a  fine  ex- 
ample of  the  typical  tufa-cone  in  its  broad  and  shallow  saucer- 
shaped  crater,  with  the  stratification  parallel  to  the  bottom 
of  the  saucer  and  to  the  original  outer  slope.  These  slopes 
have  become  deeply  trenched,  as  the  view  shows,  by  descend- 
ing waters  ;  and  since  1840  the  southern  brow  has  lost  some- 
thing of  its  boldness.  Two  other  cones  stand  in  a  line  to  the 
north  of  it,  —  the  first  a  place  of  lava  outflow.  The  three 
vents  appear  to  l^e  situated  on  a  single  line  of  fracture. 

The  Koko  Head  tufa-cones  are  situated  at  the  east  ex- 
tremity of  the  island.  The  view  (Fig.  3)  was  taken  from  the 
eastward  at  sea.  The  larger  or  more  northern  of  the  two 
cones  is  much  denuded  inside  and  out.  The  other  low  cone, 
situated  on  the  Point,  is  worn  to  its  centre  by  the  sea,  and 
has  thereby  been  made  to  exhibit  to  the  passing  vessel  (as  it 
goes  from  or  toward  Honolulu)  the  dip  of  its  tufa-beds  in- 
ward and  outward,  and  thereby  the  true  structure  of  such 
a  cone. 

Artesian  borings  on  Oaliu  afford  some  facts  bearing  on  the 
history  of  Diamond  Head  and  Punchbowl.  The  borings  were 
made  by  Mr.  J.  A.  McCandless  of  Honolulu,  and  records  of  a 
number  of  them  have  been  received  from  him  through  Prof. 
W.  D.  Alexander. 

The  following  section  is  from  James  Campbell's  well,  at 
the  west  foot  of  Diamond  Head,  not  far  from  the  sea-level. 

Thickness.        Depth. 

Gravel  find  beach  sand 50  feet  .    . 

Tufa  like  that  of  Diamond  Head 270  320  feet 

Hard  coral  rock,  like  marble 505  825 

Dark  brown  cLny 75  900 

Washed  gravel 25  925 


294  VOLCANIC   PHENOMENA 

Thickness.      Depth. 

Deep  red  clay        95  feet  1,020  feet 

Soft  white  coral 28  1,048 

Soapstone-like  rock 20  1,068 

Brown  clay  and  broken  coral 110  1,178 

Hard  blue  lava 45  1,223 

Black  and  red  clay 28  1,251 

Brown  lava        249  1,500 

The  well  went  clown  1,178  feet  before  reaching  the  solid 
lava  of  the  bottom.  In  its  upper  part  it  passed  through  270 
feet  of  tufa,  indicating  that  the  tufa-cone  extended  below  the 
sea-level  to  this  depth,  and  therefore  had  a  total  height  of  over 
1,000  feet.  Below  the  tufa,  between  the  320-foot  and  825- 
foot  levels,  there  are  505  feet  of  hard  coral  rock ;  and  then, 
on  the  1,048-foot  level,  a  28-foot  la3'er  of  soft  white  coral, 
and  at  a  greater  depth  brown  clay  and  broken  coral.  As  the 
well  is  close  by  the  west  foot  of  the  Head  and  passes  through 
so  much  of  its  tufa,  it  is  quite  certain  that  the  505-foot 
stratum  of  limestone  was  made  before  the  tufa-eruption,  and 
that  the  beds  underneath  it  mark  earlier  conditions  over  the 
site. 

As  regards  a  supply  of  fresh  water,  the  well  was  a  fail- 
ure, —  an  exception  to  the  usual  experience.  The  water 
came  up  salt,  and  a  much  stronger  brine  than  sea-water.  It 
was  under  some  pressure,  as  it  stood  a  foot  above  the  level  of 
surface  wells  near  by. 

Other  borings  have  been  made  in  Waikiki,  —  the  sea-border 
district  just  west  of  Diamond  Head.  The  section  afforded 
by  the  deepest  of  the  Waikiki  wells  is  here  inserted  for  com- 
parison. It  is  that  of  the  King's  well,'No.  2,  —  about  half  a 
mile  west  of  Diamond  Hill  and  350  yards  from  the  seashore. 

Thickness.      Depth. 

Sand  and  coral 38  feet  .     . 

AVhite  coral 22  GO  feet 

Yellow  sand 43  103 

Hard  lava        47  150 

White  coral 110  260 


OF   THE   ISLAND   OF   OAHU.  295 

Thickness.    Depth. 

Blue  clay 25  feet     285  feet 

Tough  clay  and  coral 65  350 

Blue  clay 30  380 

Hard  coral 40  420 

Soft  coral 30  450 

Tough  clay 5  455 

White  coral .     40  495 

Tough  clay 30  525 

White  coral 100  625 

Tough  clay 5  630 

Coral  and  clay 70  700 

Tough  clay ...     28  728 

Black  sand 2  730 

Lava 120  850 

In  this  well  the  upper  320   feet  probably  correspond  ap- 
proximately to  the  upper  tufa-made  portion  of  the  preceding. 
It   is  remarkable  that  tufa  is  wholly  absent,  although  the 
distance    from   the  active  vent  was   so   small ;    but   this   is 
accounted    for   by   the  direction  of   the   trade-winds,  which 
would    have   carried    the    ejected    material    seaward,  —  the 
direction    in    which    the    hill    is    elongated.     Moreover,  the 
tufa-cone,  although   1,000  feet  high,  may  have  been  thrown 
up  in  a  single  year  or  less.     Instead  of  tufa  for  the  upper 
part,  there  are  underneath  38  feet  of  sand  and  coral,  22  feet 
of  white  coral  ;    110  feet  more  of  a  coral  layer  above  the 
260-foot  level,  and  65  feet  of  "tough  clay  and  coral"  next 
above  the  350-foot  level.     Further,  beginning  with  the  380- 
foot  level,  a  coral  layer  continues  to  the  700-foot  level,  or 
for  320  feet,  with  the  exception  of  forty  feet  of  clay  divided 
between   three  layers ;    and  this   320-foot  layer  appears   to 
correspond  to  the  505-foot  layer  between  320  and  825  feet 
in  the  other  section.     The  solid  lava-stream  of  the  bottom 
of  the  well  was  reached  at  730  feet.     The  amount  of  water 
obtained  proved  that  the  lava-stream  was  one  of  those  from 
the  mountain.     It  is  overlaid  by  two  feet  of  volcanic  sand  and 
28  of  tough  clay,  the  sand  serving  to  contain  the  water  and  the 
clay  to  confine  it,  conditions  suited  to  make  the  well  a  success. 


296  VOLCANIC   PHENOMENA 

In  these  sections  the  intercalated  beds  of  so-called  "  clay  " 
vary  widely  in  position  and  thickness,  and  appear  to  be.  in 
general,  local  deposits  of  decomposed  rock  from  mountain 
streams,  or  tufa-deposits  from  one  source  or  another.  In 
another  boring  in  Waikiki,  a  bottom  of  solid  lava  was  reached 
at  375  feet ;  and  in  a  third.  Goo  Kim's  well,  at  475  feet.  The 
former  had  an  intercalated  lava-stream  at  a  depth  of  106 
feet,  and  the  other  at  150  feet.  In  Goo  Kim's  well,  which 
was  nearly  a  mile  from  the  seashore,  there  were  26  feet  of 
coral-rock  above  the  150-foot  level,  and  194  feet  of  coral 
above  the  430-foot  level,  but  with  two  intercalations  of  a 
20-foot  layer  of  "  clay  "  in  the  stratum.  The  facts  as  to  the 
varying  levels  of  the  "clay"  beds  and  the  intercalation  of 
lava-streams  show  what  accidents  the  living  species  of  the 
sea  and  its  reefs  were  exposed  to.  They  make  the  existence 
of  a  continuous  505-foot  stratum  of  coral  limestone  under- 
neath the  tufa  of  Diamond  Head  the  more  remarkable. 

The  artesian  wells  made  within  the  limits  of  the  city  of 
Honolulu  might  be  expected  to  throw  light  on  the  history  of 
Punchbowl. 

1.  A  well  in  ''  Thomas  Square,"  just  south  of  Punchbowl, 
afforded  the  following  section  :  — 

Thickness.     Depth.  ' 

Soil  G  feet,  with  6  of  black  sand  and  "  cla}'"  4    .  16  feet      .     . 

White  coral  (at  top,  the  elevated  reef )  ....  200  216  feet 

Brown  clav 44  260 

Coral    .     \ 10  270 

Brown  clay 60  330 

White  coral 50  380 

Brown  clay 80  460 

Bed  rock  or  lava,  penetrated 49  509 

2.  In  "  Mr.  Ward's  well,"  below  Thomas  Square,  on  King 
Street,  there  were  at  the  top  15  feet  of  loam  and  sand,  then 
180  feet  of  "  hard  coral  rock,"  carrying  the  depth  to  195 
feet ;  again  24  feet  of  coral  and  shells  above  the  219-foot 
level ;    and    then,  underneath    109    feet    of    "  yellow  clay," 


OF   THE   ISLAND   OF   OAHU.  297 

which  may  be  Punchbowl  tufa,  23  feet  of  coral  above  the 
39 3-foot  level,  and  107  feet  of  white  and  yellow  sand  below 
it ;  with  the  bottom  lava  at  508  feet  covered  by  four  feet  of 
quicksand.     An  abundant  How  of  water  was  obtained. 

3.  South  of  the  last,  in  the  •'  Kewalo  well,"  begun  near 
the  sea-level,  beneath  six  feet  of  black  volcanic  sand,  there 
were  50  feet  of  coral  over  a  40-foot  layer  of  hard  lava  ;  then 
190  feet  of  coral,  divided  in  two  by  an  intercalated  30-foot 
layer  of  "  clay,"  over  the  350-foot  level  ;  with  the  bottom 
lava-bed  at  620  feet. 

4.  Section  from  a  well  in  the  Palace  yard  :  — 

Thickness.      DeptU. 

Soil  4  feet,  black  sand  -i 8  feet      .     . 

Coral 64  72  feet 

Hard  lava 6  78 

White  coral 60  138 

Clay 240  378 

Coral 75  452 

Clay  and  gravel 254  707 

Lava  or  bed  rock,  penetrated 55  762 

Of  the  above  sections,  1,  2,  and  3  have  a  thick  bed  of  clay 
on  the  260-foot  to  280-foot  level ;  1,  2,  and  4  on  the  330- 
foot,  370-foot,  and  378-foot  levels  ;  1  and  2  and  3  on  460-foot, 
500-foot,  and  535-foot  levels  ;  and  No.  4,  a  layer  254  feet 
thick  on  the  707-foot  level,  or  the  bottom  rock.  It  is  possible 
that  one  or  more  of  these  of  ''  clay  "  may  be  decomposed  tufa 
of  Punchbowl  origin.  But  to  refer  all  to  this  source  would 
make  the  period  of  eruption  of  very  improbable  length. 
The  "  black  sand  "  below  the  soil  in  Honolulu  is  naturalh' 
referred  to  this  source.  But  more  investigation  is  required 
for  a  decision.  There  is  no  evidence  that  Diamond  Head  and 
Punchbowl  were  of  simultaneous  origin. 

Salt  Lake  Region.  —  The  salt  lake  of  Oaliu  occupies  a 
depression  surrounded  by  a  low  ridge,  and  is  situated  about 
three  fourths  of  a  mile  from  the  sea,  and  seven  to  eight  miles 
west  of  Honolulu.     It  is  not  at  first  apparent  that  its  site 

38 


298  VOLCANIC   PHENOMENA 

was  once  a  region  of  hot  water  and  tufa  eruptions  ;  yet  from 
the  character  of  the  tufa  and  the  direction  of  its  dip  such 
was  the  case.  There  were  evidently  several  vents  of  consid- 
erable lateral  extent,  but  of  small  force,  and  they  resulted  in 
producing  a  plain  a  mile  and  a  half  in  its  longest  or  east 
and  west  diameter,  bounded  by  a  tufa-made  ridge  150  to  375 
feet  in  height. 

Ascending  the  north  side,  or  that  away  from  the  sea,  we 
look  down  on  still  another  flat  plain  surrounded  by  a  ridge. 
In  its  western  corner  there  is  a  deep  bowl-like  crater  and  a 
small  fresh-water  lake  called  Aliamanu,  with  a  circular  wall 
of  stratified  tufa  486  feet  above  tide-level  on  its  north  side. 
In  structure  and  composition,  the  walls  resemble  those  of 
the  other  tufa-cones. 

Fragments  of  chrysolite  are  sometimes  found  in  the  tufa  of 
this  region  half  an  inch  in  diameter,  resembling  the  lai'ge 
crystals  observed  occasionally  in  some  of  the  compact  gray 
basalts  of  the  mountains.  I  observed  no  lavas  which  had 
flowed  from  any  of  these  vents. 

There  is  still  a  third  basin,  situated  to  the  west  of  the  first, 
near  the  borders  of  the  Pearl  River  lagoons.  It  is  a  flat 
plain,  nearly  circular,  surrounded  by  a  low  ridge,  and  has  an 
area  about  half  the  size  of  the  last. 

These  three  basins  occupy  together  a  region  about  twelve 
square  miles  in  extent.  The  more  northerly  is  about  fifty 
feet  above  the  lake  ;  and  the  lake  was  found  by  the  Expedi- 
tion to  be  near  the  level  of  the  sea  at  half  tide. 

The  salt  lake,  called  by  the  natives  Aliapakai,  was,  in 
October,  1840,  nearly  a  mile  wide  in  its  longer  diameter,  and 
half  a  mile  in  the  transverse,  and  occupied  about  half  the 
area  of  the  basin  in  which  it  lies.  It  had  been  supposed  to 
be  fifty  fathoms  deep,  but  the  long  line  prepared  for  sounding 
it  descended  only  sixteen  inches.  This  was  in  November, 
1840,  at  which  time  it  was  surveyed  by  officers  from  the 
Wilkes  Exploring  Expedition.     In  the  November  of  the  year 


OF   THE   ISLAND   OF   OAHU.  299 

following,  when  examined  a  second  time  by  the  author,  there 
were  but  six  inches  of  water ;  and  instead  of  finding  salt  only 
about  the  stones  of  the  shores  or  on  some  planted  twigs,  the 
whole  bottom  was  covered  with  a  crust  of  salt  averaging  three 
inches  thick,  and  hard  enough  to  support  a  team  of  horses. 
The  surface  of  the  crust  consisted  of  brilliant  cubes  of  salt, 
mostly  a  third  of  an  inch  in  their  dimensions.  In  some 
places  the  salt  stood  up  in  knobs  as  large  as  the  fist,  consist- 
ing of  clustered  crystals ;  and  there  were  columnar  or  finger- 
shaped  aggregations,  made  up  of  a  series  of  these  large  cubi- 
cal crystals,  which  had  formed  horizontally  from  the  knobs, 
or  parallel  with  the  surface  of  the  water,  instead  of  erect,  — 
a  position  evidently  due  to  currents  in  the  water  produced  by 
the  winds,  as  they  pointed  to  leeward.  They  were  quite  pure, 
and  had  no  nucleus,  excepting  a  few  granules  of  dirt  along 
the  centre.  Aliapakai  is  still  a  salt-water  lake,  at  mean-tide 
level,  and  is  about  4,000  and  3,000  feet  in  its  diameters. 
Aliamanu  is  fifty  feet  above  tide-level,  and  2,000  by  1,300 
feet  in  its  diameters.^ 

Kaneohe  Point.— The  east  point  of  Kaneohe  Bay  is  a 
small  peninsula,  eight  or  nine  square  miles  in  extent.  Ex- 
cepting the  volcanic  hills,  the  surface  is  nearly  flat,  cind  is 
formed  of  coral  limestone,  elevated  a  few  feet  above  high- 
water  level.  There  are  four  of  these  hills,  of  which  three 
have  remains  of  craters,  more  or  less  distinct.  The  largest 
of  the  craters  occupies  the  outer  extremity  of  the  peninsula. 
Its  walls  are  broken  away  on  the  western  side,  exposing  to 
view  the  bowl-shaped  cavity  within.  It  is  like  Diamond 
Hill,  except  that  the  inner  walls  are  more  furrowed.  The 
sea  washes  its  foot,  and  the  broken  condition  is  owing  to 
the  action  of  its  waters.  The  following  sketches  show 
the  outline  of  the  point  in  a  view  from  the  northwest, 
and  the   genera.1  appearance  of   the   largest  crater  (A)  and 

^  These  measurements  and  tlie  heights  above  are  taken  from  a  tracing  of  an 
unpublished  map  recently  received  from  Professor  Alexander. 


300  VOLCANIC   PHENOMENA 

an  island  (N)  off  the  point  to  the  northward  as  seen  from 
the  northeast  :  — 


Crater  A  and  the  Island  N. 

The  crater  B,  next  in  size  to  A,  stands  back  about  three 
fourths  of  a  mile  from  the  sea,  near  the  western  side  of  the 
peninsula.  In  a  distant  view  this  crater  has  a  high  conical 
form,  and  is  obliquely  truncated  at  top.  It  is  mostly  a  lava- 
cone  ;  and  black  rocks  form  a  large  portion  of  its  northern 
walls,  besides  half  filling  the  shallow  crater.  The  outer  sur- 
face is  mostly  loose  soil.  The  lava  of  the  eruption  flowed  off 
to  the  northward  toward  the  sea,  but  is  concealed  to  a  great 
extent  by  the  coral  sand-hills  that  have  accumulated  on  this 
side  of  the  peninsula. 

The  crater  C  is  also  a  lava-crater.  It  is  broken  down 
nearly  to  the  level  of  the  sea,  excepting  the  eastern  and 
western  sides,  which  stand  like  two  rocky  hills  sixty  or 
eighty  feet  high.  The  lava  is  like  that  just  described,  and 
mucli  of  it  is  broken  into  large  blocks,  which  lie  in  con- 
fusion together. 

There  is  also  a  small  rounded  elevation  half  a  mile  to  the 
southeast,  whicli  consists  of  the  same  basaltic  rocks,  althons;!! 
there  is  no  distinct  crater  at  the  present  time.  They  are  not 
connected  with  those  of  the  vents  just  described,  and  must 
have  been  ejected  at  the  spot  where  they  now  lie.  This  is, 
therefore,  a  fourth  vent. 

The  small  island  of  rock  (N)  standing  off  Kaneohe  Point 
must  be  a  remnant  of  a  fifth  cone. 

The  tufa-craters  descriljed  were  probably  formed  jorevious 


OF   THE   ISLAND  OF   OAHU.  301 

to  the  elevation  of  the  island  of  twenty-five  to  fifty  feet, 
referred  to  beyond  ;  and  if  so,  the  vents  at  the  time  of  the 
eruption  were  not  above  tlie  sea-level.  This  condition  is  that 
most  favorable  for  the  making  of  a  tufa-cone. 

West  Oaliu.  —  The  mountains  of  West  Oahu  cover  at 
the  present  time  a  much  smaller  area  than  those  of  East 
Oahu.  Their  original  dimensions  we  have  no  data  for  esti- 
mating. The  highest  peak,  Kaala,  in  the  northeast  part  of 
the  group  of  summits,  has  a  height,  according  to  the  Govern- 
ment survey,  of  3,586  feet,  —  which  is  681  feet  greater  than 
that  of  Konahuinui  ;  and  besides  this  there  are  in  the  south- 
eastern part  peaks  of  3,105  and  3,110  feet.  These  elevations 
and  the  deep  and  open  valleys  divided  off  by  sharp  ridges  are 
sufficient  evidence  that  the  mountain-range  is  but  a  small 
remnant  of  the  once  great  volcanic  mountain,  —  probably  a 
loftier  mountain  than  that  of  East  Oahu.  Denudation  has 
had  a  far  longer  time  for  its  dissecting  work,  and  has  done 
much  to  diminish  the  area  it  covers.  Whether  great  loss  has 
resulted  also  from  subsidence  is  not  ascertained. 

The  fact  that  the  volcano  of  East  Oahu  was  in  full  action 
long  after  the  extinction  of  the  western  cone  is  shown  (as  the 
author  first  observed  in  1840  and  again  in  1887)  by  the 
encroachment  of  the  eastern  lava-streams  over  its  base, 
and  the  burial    in    part    of 

the   valleys.       The    accom-  )~^      yW    ^^^  ^    >-',  '    ,   ^~ 

panying  sketch    is   a  view. 


looking  westward  from  the 
plain  that  was  made  hy  the 
encroaching  lavas  ;  it  shows 
liow  the  lavas  dammed  up  the  already  made  valleys  of  West 
Oahu,  and  forced  the  drainage  waters  to  take  a  north  or 
south  direction,  nearly  parallel  with  the  base  of  the  moun- 
tain, in  order  to  reach  the  sea.  The  courses  of  these  streams 
are  given  on  the  map.  "^he  depth  of  burial  hy  the  East- 
Oahu  lavas  was  probably  some   hundreds  of  feet. 


302 


VOLCANIC    PHENOMENA 


3.  Evidence  of  Recent  Change  of  Level. 

1.  Elevation.  —  Evidence  of  recent  upward  change  of  level 
is  afforded  by  the  elevated  coral-reef  along  the  sea-border. 
The  dotted  line  on  the  map  (Plate  XIV.)  has  already  been 
pointed  to  as  approximately  the  inner  limit  of  the  raised 
reef  ;  the  small  dotted  areas  about  Kahuku  Point,  the  prom- 
inent north  cape  of  the  island,  and  in  Laie,  the  district  next 
southeastward,  besides  others  west  of  Waimanalo,  are  the 
positions  of  hills  or  bluffs  made  of  the  reef-rock  and  consoli- 
dated drift-sands.  The  rock  is  in  some  parts  a  beautiful 
white  fine-grained  building-stone  ;  but  generally  it  has  sud- 
den transitions  in  texture  and  firmness,  and  much  of  it  is  a 
consolidated  mass  of  broken  corals,  or  else  of  standing  corals 
made  compact  or  nearly  so  with  coral-sand.  Along  southern 
or  southwestern  Oaliu  the  height  of  the  reef  is  fifteen  to 
thirty  feet ;  and  I  estimated  the  amount  of  elevation  indi- 
cated by  it  in  1840  at  twenty-five  or  thirty  feet. 


Kahuku  Bluffs  of  Coral-rock  and  Drift-sands,  with  two 
Sections  of  the  Drift-sand  Rock. 


At   the  Kalmku  blufi^s,   which   I  visited    anew   in    1887, 
the   solid   coral    reef-rock   extends  up  in   some    places   to   a 


OF   THE   ISLAND  OF   OAHU. 


;o3 


height  by  estimate  of  fifty  to  sixty  feet  above  tide-level ; 
and  this  is  surmounted  by  drift-sand  rock,  made  of  beach 
coral-sands  that  were  drifted  into  hills  on  the  coast  when  the 
reef-rock  was  submerged,  adding  twenty  feet  or  more  to  the 
height.  There  are  large  caverns  in  the  bluffs,  which  are 
mostly  witliin  the  upper  layer  of  the  coral-reef  rock  and  have 
the  drift-sand  rock  as  the  roof.  In  the  preceding  sketch  a 
faint  horizontal  line  may  be  seen  passing  by  the  top  of  the 
cavern  ;  it  separates  the  beds  of  different  origin.  The  coral 
reef-rock  consists  mostly  of  cemented  masses  and  branches  of 
corals  of  the  kinds  common  in  the  modern  reef,  and  also  has 
often  the  corals  in  positions  of  growth.  But  the  wind-drift 
beds  consist  of  sand,  and  show  the  abruptly  varying  pitch  in 
the  layers  connnon  in  wind-made  drifts,  as  represented  in 
the  two  sections  to  the  right  above. 

Another  and  more  extended  view  of  the  bluffs  is  here  added 
from  a  photograph  by  Dr.  J.  S.  Pratt,  of  New  York,  taken  on 


febESD 


Kahuku  Bluffs,  called  Kahipa  (from  a  pliotograph). 

the  5th  of  September,  1889.^  It  exhibits  finely  the  abrupt 
transition  from  the  coral-reef  rock  to  the  drift-sand  rock  by 
the  horizontal  line  of  crevices  which  erosion  has  made,  and 
also  brings  out  distinctly  the  variations  of  pitch  in  the  layers 
of  the  latter. 

The   change  of  level  along  northern  Oahu,  according  to 


1  The  author  is  indebted  for  the  photograph  to  A.  F.  Judd,  Chief- Justice  of 
Honolulu. 


304  VOLCANIC   PHENOMENA 

the  facts  from  Kahuku,  appears  to  have  been  at  least  fifty 
feet,  or  twenty  feet  greater  than  the  facts  on  the  southern 
side  indicate.  Even  with  an  accurate  measurement  of  the 
height  of  the  reef-rock  the  amount  of  elevation  would  remain 
doubtful,  because  the  coral-reefs  off  the  island  are  at  present 
rarely  up  to  low-tide  level ;  and  this  may  or  may  not  have 
been  the  fact  before  the  change  of  level  took  place. 

The  surface  of  the  elevated  reef  of  Oahu  is  exceedingly  un- 
even from  unequal  construction  and  erosion,  and  its  interior 
has  in  some  places  large  and  winding  caverns,  so  that  an 
overlying  formation,  were  there  one,  would  afford  an  example 
of  imconformability  by  denudation.  It  is  obvious  that  with 
greater  elevation  the  unevenness  would  be  as  much  greater, 
—  large  enough  to  get  the  credit,  perhaps,  of  representing  an 
interval  of  many  thousands  of  years,  although  results  of  the 
"  modern "  period  in  geology.  Denudation  works  rapidly 
among  limestones,  and  especially  so  when  the  limestones 
have  just  left  the  water,  with  the  usual  irregularities  of  upper 
surface  and  texture. 

2.  Subsidence.  —  A  former  subsidence  of  the  island  is  ap- 
parently indicated  by  the  coral-rock,  through  the  depth  to 
which  it  has  been  found  to  extend  in  Artesian  borings.  In 
these  borings,  described  above,  a  depth  of  seven  to  eight 
hundred  feet  was  found  for  the  coral-rock,  and  more  than 
one  thousand  for  broken  corals ;  and  over  seven  hundred  is 
reported  by  Mr.  McCandless  from  a  well  in  the  Eua  district, 
alwut  five  miles  west  of  Honolulu.  The  facts  lead  to  the 
inference  that  the  subsidence  amounted  to  at  least  eight  hun- 
dred feet,  and  that  it  corresponds  to  the  coral-reef  subsidence 
which  Darwin's  theory  requires.  Mr.  McCandless  informed 
me  that  fragments  of  corals  like  those  of  the  modern  reefs 
were  brought  up  from  the  various  levels. 

This  evidence  of  subsidence  to  the  amount  stated  is  not, 
however,  complete.  Doubt  remains  because  the  corals  brought 
up  in  fragments  have  not  l)een  examined  by  any  one  compe- 


OF   THE   ISLAND   OF   KAUAI.  '  305 

tent  to  decide  on  their  actual  identity  with  existing  species  ; 
I  could  not  find  that  any  of  them  had  been  preserved.  In  a 
series  of  specimens  of  the  beds  passed  through  in  an  artesian 
boring  in  Honolulu,  on  the  property  of  Mr.  J.  B.  Atherton, 
for  which  I  am  indebted  to  President  Merritt,  coral  or  shell 
sand  occurs  more  or  less  freely  in  all  the  samples,  and  some 
consist  wholly  of  such  sand,  or  of  sand  and  larger  fragments ; 
but  the  fragments  were  in  general  from  the  reef-rock,  or  if 
from  corals,  not  of  sufficient  size  for  the  identification  of 
species.  The  well  was  carried  to  a  depth  of  655  feet,  and 
beds  of  coral  and  shell  sand  were  found  at  the  following 
depths  :  between  12  and  65  feet,  70  and  190  feet,  200  and 
230  feet,  275  and  280  feet,  290  and  320  feet,  355  and 
400  feet,  455  and  480  feet,  and  505  and  515  feet.  The 
facts  are  not  sufficient  to  answer  the  question  as  to  the 
species  that  contributed  material  to  the  calcareous  beds. 

We  may  hope  that  the  study  on  the  island  of  the  specimens 
brought  up  in  future  artesian  borings  will  remove  the  doubt 
that  remains. 


III.    ISLANDS  OP  KAUAI  AND  NIHOA. 

A.    KAUAI.^ 

Kauai  is  nearly  circular  in  form,  and  has  an  average  di- 
ameter of  twenty-nine  statute  miles.  The  land  rises  very 
gradually  from  the  coast,  except  on  the  western  side,  where 
there  is  a  precipice  fronting  the  sea  of  o*ne  to  two  thousand 
feet.  Elsewhere  there  are  usually  cliffs  of  two  or  three  hun- 
dred feet,  above  which  commences  a  gently  sloping  shore- 
plain,  two  to  five  miles  wide.  This  cliff  occasionally  retreats 
inward,  leaving  a  sea-coast  plain  surrounded  by  an  amphi- 

^  This  description  of  Kauai  consists  of  extracts  from  the  author's  "  Exploring 
Expedition  Report  "  on  the  island,  which  was  based  on  explorations  for  the  larger 
part  of  a  week  in  1840. 

39 


306  VOLCANIC  PHENOMENA 

theatre  of  steep  hillsides.  The  surface  of  the  interior  is 
broken  into  ridges  and  valleys,  many  of  great  extent.  The 
loftier  summits  tower  up  with  steep,  unbroken  sides  three  or 
four  thousand  feet  above  the  other  heights  around  them,  and 
some  of  the  gorges  are  one  to  two  thousand  feet  deep.  The 
altitude  of  Waialeale,  the  highest  peak,  is  estimated  at  eight 
thousand  feet.  Toward  the  west  side  of  the  island  there  is  a 
mountain  plain  about  four  thousand  feet  above  the  sea. 

The  valleys  of  Kauai  are  as  much  more  extensive  than 
those  of  other  islands  of  the  group,  as  its  peaks  are  more 
irregular,  abrupt,  and  broken.  Hanalei  valley,  w^iich  opens 
on  the  northern  coast,  is  a  wide  plain  for  many  miles,  though 
becoming  a  narrow  gorge  above  ;  it  separates  a  ridge  on  the 
east  from  the  mass  of  mountains  on  the  west.  Hanapepe 
valley  opens  on  the  opposite  or  southern  shore,  and  is  one 
of  the  most  extensive  in  the  island  and  also  the  one  most  to 
be  enjoyed  for  its  beauty.  Its  waters,  like  those  of  Hanalei, 
rise  in  part  from  the  peak  Waialeale.  At  the  "  Falls,"  four 
miles  up  the  valley,  "  we  w^ere  in  an  amphitheatre  of  surpass- 
ing grandeur,  to  which  the  long  defile  with  its  fluted  or  Gothic 
walls,  decorated  with  leaves  and  flowers  and  a  succession  of 
cascades,  made  a  fit  entrance-way.  On  the  left  there  stood, 
apart  from  the  walls,  an  inclined  columnar  peak  or  leaning 
tower,  overhanging  the  valley.  From  a  gorge  on  the  right, 
where  the  basaltic  rocks  stood  out  either  side  in  curved 
ascending  columns  as  if  about  to  meet  above  in  a  Gothic 
arch,  a  stream  leaped  the  precipice  and  fell  in  dripping  foam 
to  the  depths  below,  where,  gathering  again  its  strength,  it 
went  on  its  shaded  way  down  the  gorge."  The  Wailua,  the 
chief  river  of  eastern  Kauai,  also  has  its  noted  w^aterfall ; 
but  it  is  situated  within  the  shore  plain,  two  and  a  half 
miles  from  the  sea.  The  stream,  about  thirty  yards  wide, 
divides  and  descends  a  precipice  of  one  hundred  and  sixty 
feet.  For  the  last  two  miles  of  its  course  the  width  is  about 
fifty  yards,  and  the  depth  sufficient  for  canoes ;  but,  owing  to 


OF   THE   ISLAND   OF   KAUAI.  307 

the  sand-bar  at  its  mouth,  its  fifty  yards  at  the  end  become 
three  or  four.  Nearly  all  the  smaller  streams  are  closed  in 
a  similar  way  by  bars  made  of  coral-sands,  and  so  com- 
pletely that  the}^  may  generally  be  crossed  at  mouth  on  dry 
land,  the  water  escaping  through  the  sands. 

Among  the  lofty  summits  of  the  interior  there  is  no  well- 
defined  crater.  The  ridges,  as  they  reach  toward  the  sea,  are 
very  distinctly  seen  to  decline  gradually  into  the  shore  plain, 
this  plain  being,  in  fact,  but  the  base  or  foot  of  the  mountains, 
continuing  the  slope  of  the  ridges  to  the  sea.  Moreover,  the 
plain  and  the  ridges  show  not  merely  a  continuity  of  surface, 
but  also  of  internal  structure.  The  river  channels  which  in- 
tersect it,  like  those  of  the  dividing  plain  of  Oahu,  are  often 
three  hundred  feet  deep,  and  have  a  uniform  stratification, 
which  extends,  without  changing  essentially  its  inclination 
or  general  character,  far  toward  the  centre  of  the  island. 

The  layers  are  remarkably  regular,  and  dip  with  the  slope 
of  the  plain  at  an  angle  of  one  to  five  degrees.  They  are  so 
nearly  horizontal  that  the  inclination  is  often  hardly  appar- 
ent. The  dip  is  away  from  the  interior  toward  the  shores, 
the  layers  rising  gradually  toward  the  interior  from  the 
southern,  eastern,  and  northern  sides.  The  layers  differ 
much  in  thickness,  and  enlarge  toward  the  interior  ;  within 
five  miles  of  the  sea  they  vary  from  ten  to  one  hundred  feet 
in  thickness  :   twenty  to  twenty-five  feet  is  the  mean. 

The  rock  is  the  usual  light  gray  basalt  found  on  Oahu  and 
to  the  eastward.  It  varies  from  scoriaceous,  recent-looking 
lava  to  the  most  compact.  Chrysolite  is  usually  present,  and 
in  the  Hanapepe  valley  masses  that  had  come  from  the  moun- 
tains contained  crystals  an  inch  or  more  in  tlieir  several  di- 
mensions. A  tendency  to  a  columnar  structure  is  common  in 
the  layers,  and  in  some  regions,  as  in  the  valley  just  men- 
tioned, the  columns  are  well  defined  and  a  marked  feature 
in  the  scenery. 

Curved   columns   often   occur  in    places    where  at  first   it 


308  VOLCANIC   PHENOMENA 

seems  difficult  to  account  for  them  by  reference  to  the  posi- 
tion of  the  cooling  surfaces.  The  middle  or  interior  of  a 
layer,  which  in  other  parts  is  vertically  columnar,  pre- 
sents at  times  singular  examples  of  contorted  columns ;  the 
straight  columns  curve  to  the  right  or  left  for  a  short  dis- 
tance, and  then  gradually  resume  their  original  direction. 
The  explanation  may  be  found  in  the  fact  that  over  streams 
of  cooling  lava  steam-holes  remain  for  many  months,  and 
sometimes  for  a  year  or  more  after  the  eruption  has  ceased, 
emitting  hot  air  and  vapors ;  and  under  such  circumstances 
the  cooling  of  the  interior  must  take  place  very  unequally ; 
curvatures  of  various  forms  might  thus  be  produced,  and 
still  derive  their  peculiarities  from  the  position  of  the  cool- 
ing surfaces,  or,  what  is  equivalent,  the  direction  in  which 
the  heat  was  drawn  off. 

Besides  the  mountains  and  hills  which  along  with  the  shore 
plain  constitute  the  great  mass  of  the  island,  there  are  some 
ridges  near  the  eastern  shores  which  appear  to  be  distinct 
from  the  rest,  since  they  lie  between  the  border  plain  and  the 
sea.  One  of  these  is  the  Hoary  Head  Ridge,  which  stands 
along  the  southeast  corner  of  the  island  and  passes  inward 
toward  Koloa.  It  has  an  abrupt  front  toward  the  interior, 
and  an  uneven  serrated  outline.  Wailua  River  cuts  through 
one  of  the  ridges  about  half  a  mile  from  the  sea ;  and  near 
by  parallel  layers  of  lava  were  distinct  to  the  summit  of  each 
of  the  rugged  peaks,  dipping  eight  to  ten  degrees  northeast- 
ward or  nearly  toward  the  sea.  A  similar  dip  occurs  in  the 
summits  a  few  miles  south  of  Wailua,  near  Nawiliwili.  Eight 
or  nine  miles  north  of  Wailua,  back  of  Anahola,  on  the  north- 
east shore  of  tlie  island,  there  is  a  high  border  ridge  with 
needle  summits  in  which  the  usual  stratification  is  apparent. 
One  of  the  curiosities  of  the  place  is  a  hole  through  one  of 
the  summit  needles  near  its  base. 

Kauai  has  also  its  lateral  craters  near  the  sea  in  the 
vicinity  of  Koloa,  much  resembling  those  of  Oahu.     An  area 


OF   THE   ISLAND   OF   KAUAI. 


309 


KoLOA  Volcanic  District. 


of  eight  or  ten  square  miles,  containing  several  cones,  is  rep- 
resented in  the  accompanying  map.  Black  lavas,  as  bare  as 
many  of  the  lava-fields  of 
Mount  Loa,  form  the  surface 
over  a  large  part  of  the  area, 
;ind  the  lava-streams  often 
have  a  ropy  exterior  and  are 
bulged  up  into  domes  and 
ridges  like  modern  lava- 
streams.  One  of  the  domes 
not  far  from  Koloa  contained 
within  an  open  space  or  cav- 
ern, ten  feet  high,  twenty 
broad,  and  fifty  long,  and  the 
bulged  layer  which  made  the 
cover  was  about  five  feet  thick; 

it  was  evidently  a  vapormade  bulge.  The  roof  was  very 
rough,  but  not  stalactitic.  The  waves  of  the  ocean,  driving 
over  the  black  rocks  into  dark  recesses,  and  rising  in  copious 
jets  or  dashing  into  foam,  afford  majestic  sights  wherever 
seen  about  these  volcanic  islands  ;  and  some  of  the  spout- 
holes  of  Koloa  are  unusually  grand. 

The  Koloa  lava  is  the  common  black  or  brownish  black, 
somewhat  cellular  basalt  of  such  regions;  and  it  is  sometimes 
columnar.  Along  the  banks  of  a  stream  there  are  well-defined 
prisms,  about  eighteen  inches  in  diameter.  The  horizontal 
joints  are  flat,  not  concave.  The  number  of  volcanic  hills  is 
five  ;  and  among  them  one  contains  two  craters,  and  another 
three  craters,  as  shown  in  the  preceding  map.  With  one  ex- 
ception, they  are  low,  with  a  rounded  contour  and  barren 
earthy  sides,  looking  as  if  made  of  dark-colored  brickdust. 

The  one  exception,  called  the  Old  Crater,  is  represented 
to  the  left  in  the  accompanying  sketch.  It  stands  about  one 
liundred  and  fifty  feet  above  the  plain.  Its  steep  and  ragged 
summit    consists  of   dark  brown  lava  and  scoria.     The  bare 


310 


VOLCANIC  PHENOMENA 


sides  are  smooth  till  near  the  summit,  where  the  lava  breaks 
out  in  columns,  so  rude  and  jagged  as  scarcely  to  be  col- 
umns, yet  appearing  columnar  from  below.  It  forms  a  nar- 
row wall,  or  crest,  broken  by  numerous  rents,  and  is  mostly 


The  "Old  Crater"  and  Others  of  Koloa. 

wanting  on  the  east-southeast  and  west-northwest  sides.  The 
crater  is  about  one  hundred  and  fifty  yards  wide  at  top,  and 
has  a  depth  of  thirty  or  forty  yards.  The  surface  within 
is  smooth,  and  consists  of  red  earth,  like  the  lower  slopes 
of  the  exterior. 

The  lava  of  the  crest  owes  its  roughness,  in  part,  to  a 
thin  laminated  structure  and  numerous  vertical  fractures. 
The  laminae  are  from  half  an  inch  to  two  inches  thick ;  and 
although  not  easily  separated,  they  stand  out  prominently 
over  the  worn  or  decomposed  surface.  The  rock  has  been 
rendered  very  irregular  froin  disintegration,  and  at  top  the 
columns  are  sometimes  unevenly  tapering.  Besides  these 
sources  of  its  rough  features,  the  walls  within  are  covered 
with  lava  in  twisted  shapes,  forming  patches  plastered  on 
the  surface  or  hanging  in  stalactites.  The  rock  of  the  crest 
is  very  cellular,  and  much  of  it  is  scoriaceous. 

To  the  eastward  of  the  Old  Crater,  about  three  fourths  of 
a  mile,  there  is  the  small  hill,  with  evenly  rounded  top,  rep- 
resented in  the  foreground  of  the  preceding  sketch.  It  has 
a  shallow  cavity,  about  one  hundred  feet  in  diameter,  broken 
down  on  one  side,  with  walls  of  semi-columnar  lava  on  the 
other.     The  lava  is  lamellar  in  structure,  like  that  of   the 


OF   THE   ISLAND   OF   KAUAI.  311 

Old  Crater,  and  the  surface  is  covered  with  ropy  and  twisted 
slag-like  scoria. 

The  lavas  of  the  Koloa  district  probably  issued  from  some 
or  all  of  these  craters,  and  from  fissures  in  the  plain.  All 
the  hills,  with  one  exception,  lie  nearly  in  the  same  line; 
and  hence  a  large  fissure  was  probably  opened  in  the  direc- 
tion of  this  line,  from  which  the  eruptions  took  place,  certain 
points  along  the  fissure  becoming  vents  for  continued  erup- 
tion and  giving  origin  to  the  cones,  —  the  usual  mode  of 
action  on  Hawaii  and  in  other  volcanic  regions.  In  the  Old 
Crater  the  lavas  appear  to  have  boiled  up  to  the  top,  and 
thus  formed  the  crest,  as  a  ridge  is  formed  around  a  lake  in 
Kilauea,  and  then  subsided  again,  leaving  the  sides  covered 
with  pendent  masses  of  scoria. 

The  red  soil  of  the  Koloa  district  resembles  that  in  other 
parts  of  the  island.  The  effect  of  the  growth  of  vegetation 
upon  it,  in  bringing  the  iron  into  new  combinations  with  or- 
ganic acids,  is  seen  about  Koloa,  where  there  is  a  foot  or  so 
of  dark  loam.  The  cavernous  surface  of  these  lavas  appears 
to  soak  up  whatever  waters  fall,  and  the  region  is  mostly 
barren  except  in  the  immediate  vicinity  of  Koloa,  where 
there  is  a  fine  stream  and  some  marshy  soil. 

The  island  of  Kauai  is  thus  like  the  other  Hawaiian 
islands,  in  (1)  the  generally  basaltic  character  of  its  lavas  ; 
(2)  the  dependence  of  its  slopes,  and  of  the  dip  of  the  lava- 
streams  in  the  central  mountains  and  of  the  border  plain,  on 
the  pericentric  discharges  of  a  great  central  vent,  once  exist- 
ing in  the  region  to  which  the  dips  around  point ;  (3)  the 
gentle  angle  of  the  lava-flows  from  the  vent,  ordinarily  one 
to  five  degrees,  and  often  hardly  distinguishable  from  hori- 
zontality ;  and  also  (4)  in  its  recent-looking  lateral  cones. 
Moreover,  the  valleys  and  peaks  indicate  that  its  fires  long  ago 
ceased,  —  as  long  ago  as  those  of  eastern  Oahu,  if  not  before. 

The  elevated  plain  in  the  western  part  of  the  island,  about 
four  thousand  feet  high,  needs  special  investigation  as  to  the 


312  VOLCANIC  PHENOMENA  OF  KAUAI. 

dip  of  the  layers  ;  and  so  also  the  lofty  precipice  on  the  side 
fronting  to  the  northwestward.  There  may  be  indications,  as 
has  been  supposed,  of  a  second  great  cone,  and  of  the  loss 
of  a  part  of  its  mass  by  a  profound  subsidence.  The  fact 
that  this  precipice  of  Kauai  has  the  same  direction  as,  and 
is  nearly  coincident  in  line  with,  that  of  eastern  Niihau,  the 
island  to  the  southwest,  and  that  Niihau  has  beyond  ques- 
tion lost  the  larger  part  of  the  original  cone  or  dome  by 
engulfment,  are  evidence  that  the  subsidence  appealed  to 
is  not  an  improbability. 

With  regard  to  the  origin  of  the  eastern  shore-ridge,  there 
remains  much  doubt.  It  may  be  the  result  of  a  faulting  and 
uplifting  of  the  strata  ;  yet  this  is  not  probable.  The  shore 
plain,  inside  of  it,  is  evidence  that  no  extensive  degradation 
has  taken  place  over  the  surface  of  this  plain  since  it  was 
formed.  It  may  be  that  we  must  look  far  back  into  the  his- 
tory of  Kauai  for  its  explanation,  to  a  period  before  the  ma- 
terial of  the  present  mountains  was  ejected,  when  an  earlier 
cone  was  broken  down,  and  this  ridge  was  left,  as  Somma 
antedates  the  present  cone  of  Vesuvius.  In  this  case  the 
shore  plain  must  have  derived  its  lavas  from  the  volcanic 
mountain  which  subsequently  rose. 

The  Interiok  of  Volcanic  Mountains. 

Dissected  volcanic  mountains,  like  Kauai,  reveal  facts 
with  regard  to  the  earlier  progress  of  the  cone  —  that  is, 
the  earlier  work  of  the  volcano  —  which  in  some  cases 
enable  the  investigator  to  mark  off  stages  in  its  history. 
The  island  of  Kauai,  therefore,  deserves  study,  as  much  as 
the  more  famous  Hawaii  at  the  other  end  of  the  group. 
One  significant  fact  observed  by  the  author  in  1840  has 
been  mentioned,  —  the  much  greater  thickness  of  the  streams 
or  layers  of  lava  in  the  interior,  —  a  thickness  of  a  hundred 
feet  occurring  within  five  miles  of  the  sea.     The  observa- 


THE   INTERIOR  OF  VOLCANIC   MOUNTAINS.  313 

tions  of  the  author  the  previous  year  .on  Tahiti  had  proved 
that  island  to  be  essentially  the  remains  of  a  single  great 
volcanic  mountain,  the  stratification  along  the  sides  of  the 
valleys  having  a  regular  dip  of  usually  3°  to  5°  seaward  (see 
map  of  Tahiti,  p.  375).  Moreover,  the  fact  was  observed 
that  the  ''  layers  become  thicker  toward  the  interior."  It  is 
stated  in  the  author's  "  Report  "  that  "five  or  six  miles  from 
the  sea,  bluffs  of  a  thousand  feet  constitute  apparently  a 
single  continuous  bed,  or  at  least  there  is  no  line  of  demar- 
cation separating  it  into  parts.  Not  unfrequently  the  whole 
height  exhibits  a  continuous  columnar  structure  throughout." 
In  the  face  of  one  precipice  in  the  Matavai  valley  about  five 
hundred  feet  high,  where  the  columnar  structure  w\as  dis- 
played with  considerable  perfection,  the  columns,  which  were 
ten  to  twenty  inches  in  diameter,  were  at  several  places  con- 
verged to  a  point  and  then  restored  to  parallelism.  The 
breadth  occupied  by  one  of  these  converging  clusters  was 
about  ten  feet ;   but  others  were  larger. 

The  conclusion  follows  that  the  volcano  in  its  earliest 
outflows  poured  out  its  deepest  floods,  and  afterward  the 
shallower  streams,  producing  the  ordinary  tliin-stratified 
structure  of  the  exterior  and  border  resrion. 

Tahiti  illustrates  other  points  with  regard  to  the  occasional, 
if  not  common,  condition  of  the  central  re^i-ion  of  the  o-reater 
volcanic  mountains,  —  that  is,  the  region  of  the  lava-column. 
The  author  observes^  that  "in  the  lofty  peak  of  Orohena  the 
massive  structure  is  still  more  remarkable.  In  the  view 
from  the  top  of  Aorai  (figure  on  p.  378)  a  surface  of  three  to 
four  thousand  feet  is  exposed,  almost  bare  of  vegetation,  and 
throughout  it  no  trace  of  layers  was  detected.  Instead,  indi- 
cations of  a  columnar  structure  were  observed.  It  was  owing, 
apparently,  to  this  even  continuity  of  surface  that  the  usual 
amount  of  vegetation  was  not  spread  over  it,  for  there  was 

1  Exploration  Expedition  Geological  Report  on  Tahiti,  Bolabola,  Maurua, 
pp.  294,  301,  305  ;  New  South  Wales,  p.  498. 

40 


314  VOLCANIC   PHENOMENA  OF   KAUAI. 

only  here  and  there  a  crevice  that  could  sustain  even  a 
bush." 

Further,  the  thick  layers  of  the  interior  differ  from  the 
thin-bedded  in  being  much  less  vesicular,  and  "  usually  com- 
pact with  only  minute  cellules,  if  any."  Six  to  eight  miles 
up  the  Papenoo  valley  rounded  stones  of  a  whitish  crystalline 
dioryte-like  rock  were  found  by  the  author,  which  must  have 
come  from  some  of  the  central  heights  ;  and  they  suggested 
the  view  that  the  massive  character  of  the  rock,  through 
thousands  of  feet,  was  due  to  the  cooling,  on  the  decline  of 
the  volcano,  of  the  great  central  mass  of  lava,  or  that  of 
the  lava-column ;  and  that  the  coarse  crystallization  of  part 
of  the  rock  was  owing  to  the  extreme  slowness  with  which 
cooling  in  so  thick  a  mass  would  go  forward.  On  the  island 
of  Bolabola,  another  of  the  Society  group,  Ellis  found,  he 
states,  "masses  of  rocks  composed  of  feldspar  and  quartz  ;  " 
and  on  Maurua,  a  species  of  granite  is  reported  as  being  in 
considerable  abundance.  The  author's  "  Expedition  Report," 
in  citing  these  facts,  adds  that  the  rocks  are  very  similar 
to  a  grayish  Vv^hite  feldspathic  rock  observed  by  him  at 
Prospect  Hill,  in  New  South  Wales,  which  there  graduates 
through  porphyritic  kinds  into  an  ordinary  black  basalt. 

Such  facts  led  the  author  in  1839  and  1840  to  the  conclu- 
sion, which  he  has  ever  since  held,  that  grade  of  crystalliza- 
tion in  crystalline  rocks  is  an  expression  of  rate  of  cooling  ; 
that  "  although  the  liquid  rock  of  volcanic  outflows  generally 
cools  without  distinctly  visible  crystallization,  or  with  only 
crystals  of  feldspar,  or  of  augite,  in  a  compact  base,  "  the 
cooling  is  sometimes  sufficiently  gradual  to  allow  of  the 
whole  crystallizing  ;  and  in  this  case  the  texture  throughout 
is  crystalline  and  the  rock  much  resembles  a  granite."  And 
further,  that  "  particular  crystalline  rocks  have  no  necessary 
relation  to  time  on  our  globe,  except  so  far  as  time  is  con- 
nected with  a  difference  in  the  earth's  temperature  or  climate, 
and  also  in  oceanic  or  atmospheric  pressure  ;  for  if  the  ele- 


THE   INTERIOR   OF   VOLCANIC   MOUNTAINS.  315 

merits  are  at  hand,  it  requires  only  different  circumstances 
as  regards  pressure,  heat,  and  slowness  of  cooling,  to  form 
any  igneous  rock  the  world  contains."  ^  Thanks  to  the 
investigations  of  Allport  and  Judd,  and  in  this  country  of 
Messrs.  Hague  and  Iddings,  this  not  hasty  inference  is  now 
an  established  fact  in  the  science  of  igneous  rocks. 

Elevation  of  the  Island. 

Kauai  has  its  growing  coral-reef  and  its  elevated  reefs,  and 
in  these  respects  resembles  Oahu. 

The  growing  reef  is  narrow,  and  is  absent  altogether  on 
the  side  of  the  mountain  cliff,  where  the  depth  is  too  great. 
The  beaches  of  coral-sand  are  quite  extensive  on  the  eastern 
or  windward  shores.  A  low  beach-made  ridge  continues  along 
them,  seldom  interrupted,  which  is  raised  from  ten  to  twenty 
feet  above  high  tide,  and  in  some  places,  where  drifted  by 
the  winds,  thirty  to  thirty-five  feet.  About  tlie  mouths  of 
the  streams  the  sands  are  often  thrown  up  so  as  to  close  the 
stream  entirely,  as  far  as  appears  at  the  surface,  and  deltas 
of  small  extent  ai-e  sometimes  formed,  as  off  the  mouth  of 
the  Hanalei  valley,  at  Anahola,  and  at  other  places. 

The  deposits  contain,  in  some  parts,  the  shells  and  corals 
of  the  present  shores  but  little  altered,  and  resembling  beach- 
worn  specimens.  There  is  a  small  bank  of  this  kind  near  the 
mouth  of  the  Hanalei  River,  four  or  five  feet  above  the  existins: 
level  of  the  sea.  But  such  beds  of  shells  are  not  connnon,  and 
by  far  the  greater  part  is  without  a  fragment  larger  than  a 
grain  of  sand.  It  is  remarkable,  also,  that  these  sand  de- 
posits, formed  at  the  mouth  of  a  river  fifty  yards  wide,  should 
be  nearly  pure  from  mountain  detritus.  The  hills,  two  to 
three  miles  back,  are  covered  with  loose  soil,  and  the  banks 
of  the  stream,  beyond  the  termination  of  the  coral-sand  de- 
posit, consist  of  soft  earth  from  the  adjoining  declivities ;  yet 

^  Exploration  Expedition  Geological  Report,  |jp.  377,  378. 


316 


VOLCANIC  PHENOMENA  OF  KAUAI. 


it  is  rare  to  find  a  basaltic  pebble  in  the  layers,  and  there  is 
but  a  trace  of  earthy  material.  A  few  scattered  points  of  a 
brown  color  and  some  of  chrysolite  may  be  detected.  Facts 
of  this  kind  show  how  uncertain  is  the  evidence  which  a  par- 
ticular deposit  may  present  with  regard  to  the  nature  of  the 
surface  of  the  country  adjoining,  or  the  amount  of  life  in  the 
waters.  The  fact  stated  is  actually  no  more  remarkable  than 
the  freedom  of  tlie  present  beach  from  basaltic  material,  for 
all  these  accumulations  have  had  a  beach  origin. 

There  are  also  solidified  beach-deposits  analogous  to  the 
drift  sand-rock  of  Oahu,  and  as  remarkable  in  character. 
One  of  the  ridges  on  the  shores  of  the  Koloa  volcanic  district 
is  here  represented.     It  forms  a  chff  of  thirty-five  feet ;  the 


Bluff  of  Calcareous  Drift-sands. 

cliff  appears  to  be  undergoing  degradation  from  the  action  of 
the  sea,  and  masses  of  large  size  are  now  lying  at  the  foot. 
The  ridge  consists  of  a  laminated  calcareous  rock,  the  thin 
layers  of  which  lap  over  the  ridge,  exhibiting  full  proof  of 
its  drift  origin.  The  dip,  where  greatest,  amounts  to  twenty- 
five  degrees.  In  some  parts  the  rock  is  compact  and  impal- 
pable ;  but  generally  it  has  a  sandy  texture,  though  seldom 
friable.  The  rains  have  worn  or  eroded  the  surface  quite 
largely  ;  but  in  some  places,  where  the  waters  have  stood  in 
cavities,  the  interior  of  the  cavities  has  become  hardened 
by  infiltrating  lime,  and  bowl-shaped  depressions  have  been 
formed,  lined  with  a  crust  of  compact  limestone  three  fourths 
of  an  inch  thick  and  having  no  trace  of  a  sandv  structure. 


VOLCANIC   PHENOMENA  OF  NIHOA.  317 

This  ridge  is  evidence  of  a  change  of  level  in  the  island  of 
Kauai,  though  to  what  extent  is  not  yet  known.  It  was 
probably  about  as  great  as  that  of  Oahu. 


B.    NIHOA,  OR   BIRD   ISLAND. 

The  island  of  Nihoa  is  a  remnant  of  a  small  half -submerged 
cone,  fifty-two  hundred  feet  long  and  sixteen  hundred  feet  in 
mean  width,  situated  about  three  hundred  miles  west-north- 
west from  Kauai.  It  was  surveyed  in  July  of  1885  by  Rev. 
Sereno  E.  Bishop,  acting  as  assistant  in  the  Hawaiian  Govern- 
ment Survey ;  and  the  following  facts  are  from  his  report :  — 

The  island  appears  to  be  made  up  of  the  north  side  and  of 
a  portion  of  the  east  and  west  sides  of  a  relatively  small  cone. 
The  sea  occupies  its  open  centre  in  a  large  bay.  From  this 
bay  there  is  for  the  most  part  an  abrupt  rise  of  forty  to 
two  hundred  feet,  and  then  a  gradual  rise  to  the  summit  of 
the  cliffs  which  face  the  sea  on  the  east,  north,  and  west 
sides.  The  highest  part  to  the  northwestward  is  900  feet 
above  tide-level,  and  to  the  northeastward  869  feet. 

The  island  consists  of  scoriaceous  layers  made  of  well- 
cemented  fragments,  and  has  much  loose  scoria  over  the  ashy 
soil  of  the  surface.  It  is  intersected  by  a  great  number  of 
perpendicular  dikes,  "perhaps  forty  or  fifty,"  from  two  to 
ten  feet  wide,  having  a  nearly  parallel  course  from  east  to 
west.  Soundings  about  the  island  are  required  to  obtain  an 
idea  of  the  form  and  size  of  tlie  volcanic  mountain  of  which 
it  is  a  summit  cinder-cone. 

The  island  of  Kaula,  twenty  miles  southwest  of  Niihau, 
was  found  by  Mr.  Bishop  to  be  a  cone  of  cinders  or  tufa, 
much  like  Punchbowl  on  Oahu ;  and  Leliua,  an  island  near 
the  north  shore,  was  of  the  same  general  character.  Kaula 
and  Lehua  are  probably  lateral  cones  of  Niihau,  made  by 
submarine   eruptions. 


318  PETROGRAPHY   OF   THE   HAWAIIAN   ISLANDS. 

IV.    PETROGRAPHY    OF    THE    HAA^AIIAN   ISLANDS. 

BY    EDWARD    S.    DANA. 

For  our  present  knowledge  of  Hawaiian  lavas  we  are  in- 
debted in  the  first  place  to  the  general  descriptions  of  J.  D. 
Dana  in  the  "  Geology  of  the  Exploring  Expedition  "  (1849), 
and  W.  T.  Brigham  in  his  "  Notes  ^  on  the  Volcanoes  of  the 
Hawaiian  Islands"  (1868);  also  C.  E.  Dutton  (1884)  and 
others.  On  the  other  hand,  on  the  petrographical  side, 
there  have  been  published  the  microscopic  study  of  basaltic 
glass  of  Hawaii,  especially  Pele's  Hair,  by  Krukenberg,''' 
in  1877 ;  a  paper  by  Cohen,^  devoted  chiefly  to  the  glassy 
basaltic  lavas  of  Hawaii ;  brief  descriptions  of  isolated  speci- 
mens of  nepheline  basalts  believed  to  have  come  from  Oahu, 
by  Wichmann  *  and  by  Rosenbusch  ;  ^  tinally,  a  recent  memoir 
by  Silvestri,*^  describing  a  series  of  ancient  and  modern  lavas 
from  Kilauea  collected  by  Professor  Tacchini  in  1883, 

The  specimens  —  the  results  of  whose  study  are  detailed  in 
the  following  pages  —  were  collected  by  Prof.  J.  D.  Dana  on 
his  trip  to  the  Hawaiian  Islands  in  1887,  and  by  the  Rev. 
E.  P.  Baker,  of  Hilo,  in  1888.  The  former  were  from  Kilauea 
and  parts  of  the  coast  region  of  Hawaii,  and  from  Maui  and 
Oahu  ;  the  latter  chiefly  from  the  summit  region  of  Mount 
Loa,  and  the  summit  crater  Mokuaweoweo,  but  partly  also 
from  the  cavern  near  Hilo,  in  the  lava-stream  of  1880-1881, 
remarkable  for  its  stalactites,  of  which  many  fine  specimens 
were  included.^ 

1  Memoirs  of  the  Boston  Society  of  Natural  History,  vol.  i.  part  iii. 

2  Mikrographie  der  Glasbasalte  von  Hawaii,  petrographische  Untersuchung  von 
C.  F.  W.  Krukenberg,  Tiibingen,  1877.     Also  see  preceding  page  161. 

3  N.  Jahrbuch  fUr  Mineralogie,  etc.,  1880,  ii.  23. 

4  Jahrbuch,  1875,  p.  172. 

s  Mikroskopische  Physiographie  der  massigen  Gesteine,  1877,  p.  510. 
«  Comitato  Geologico  d'  Italia,  Bolletino,  1888,  xix.  128-143,  168-196. 
'  Mr.  Baker's  extended  trip  over  Hawaii,  which  comprised,  besides  an  explora- 
tion of  the  summit  crater,  a  visit  to  the  sources  of  several  of  the  great  lava-streams, 


PETROGRAPHY   OF   THE   HAWAHAN   ISLANDS.    *        319 


Mt.  Loa:   Lavas  of  its  Summit  Crater,  Mokuaweoweo, 

AND    OF   ITS    LaVA-STREAMS. 

Of  the  summit  specimens  collected  ])\  Mr.  Baker,  a  consid- 
erable pvxYt  are  from  the  talus  within  the  southern  crater  of 
Mokuaweoweo  ao-ainst  the  neck  between  it  and  the  central 
pit.  (See  Plate  X.)  A  number  of  others  are  from  the  east- 
ern side  of  the  central  i3it ;  and  in  the  case  of  scattering 
specimens,  the  special  source  is  mentioned  more  minutely 
beyond,  when  interest  seems  to  attach  to  it. 

In  general  it  may  be  said  that  all  the  specimens  in  hand 
from  Mount  Loa  belong  to  the  same  class  of  basaltic  lavas, 
although  they  vary  widely :  in  color,  from  dark  gray  to 
light  gray  or  dull  brick-red  ;  in  structure,  from  compact  to 
highly  cellular  or  vesicular,  and  from  those  of  uniform  grain 
to  those  which  are  prominently  porphyritic  with  chrysolite 
or  feldspar  ;  and  in  composition,  from  the  very  highly  chryso- 
litic  kinds  to  the  feldspathic  or  augitic  forms  with  little  or 
no  chrysolite.  Specimens  of  pumice-like  scoria  are  largely 
represented  in  the  collection. 

The  specimens  may  be  divided  pretty  sharply  into  two 
groups  ;  and  besides,  there  are  several  other  types  more  or 
Jess  distinct  from  these. 

Clinkstone-Jll'e  Basalt.  —  The  first  of  these  doubtless  in- 
cludes the  rock  which  former  observers  have  spoken  of  as 
resembling  phonolite.  Microscopically  it  has  a  uniform  fine- 
grained texture,  for  the  most  part  free  from  vesicles  and  ap- 
parently compact,  though  often  found  on  closer  examination 
to  be  minutely  porous.  The  color  varies  from  a  dark  bluish- 
gray  to  light  gray,  and  to  dull  brick-red  or  brown,  the  grayish 

was  undertaken  in  order  to  make  the  collections  of  rocks  and  gather  facts  with 
regard  to  the  ernptions,  and  some  extracts  from  his  notes  are  published  in  -the 
"  American  Journal  of  Science,"  xxxvii.  52.  The  results  have  proved  to  be  of  very 
great  interest.  The  specimens  number  about  seventy,  exclusive  of  the  scoria  and 
pumice,  and  of  these  fifty  have  been  subjected  to  microscopic  study. 


320  PETROGRAPHY   OF   THE   HAWAIIAN   ISLANDS. 

kinds  being  the  most  common.  The  siDecihc  gravity  varies 
from  2-82  to  3-00.  Some  of  the  separate  determinations  on 
fragments  freed  from  air  by  boiling  are,  —  3-00,  2-94,  3-00, 
2-87,  2*82,  3-00,  2*82.  Many  of  these  specimens,  as  taken 
from  the  talus  between  the  central  and  southern  craters,  are 
in  the  form  of  thin  slabs,  and  their  resemblance  to  clinkstone 
in  the  hand  specimen,  though  not  going  beyond  external 
asi^ect,  is  sufficiently  close  to  explain  their  having  been  so 
named.  As  regards  composition  the  rocks  of  this  type  are 
most  strongly  marked  by  the  fact  that  the  chrysolite,  which 
is  so  common  in  large  grains  in  the  other  specimens  to  be 
described,  is  absent  or  only  sparingly  present. 

The  microscopic  characters  of  this  group  of  fine-grained 
compact  rocks  are  also  such  as  readily  to  distinguish  them 
from  the  other  forms.-  In  general,  they  consist  of  augite  and 
plagioclase,  with  titanic,  or  magnetic  iron,  or  both,  prominent, 
but  with  little  or  no  chrysolite.  Their  most  interesting  fea- 
ture is  the  form  taken  by  the  augite,  which  is  only  excep- 
tionally developed  as  an  idiomorphic  constituent,  but  on  the 
other  hand  is  not  simply  a  formless  substance  filling  the 
spaces  between  the  feldspar.  It  is  uniformly,  though  with 
varying  degrees  of  distinctness,  grouped  in  radiating  forms, 
fan-shaped  or  feather-like,  of  great  variety  and  beauty. 

This  structure  is  eminently  characteristic  of  this  group  of 
rocks.  It  is  shown  best  in  a  fine-grained  purplish-colored 
specimen  (G.  =  2-82).  This  is  seen  under  the  hand-glass 
to  be  minutel}^  porous  though  not  properly  vesicular,  with 
minute  slender  red  crystals  (augite)  projecting  into  the  cav- 
ities. An  occasional  grain  of  chrysolite  can  be  detected  in 
the  mass,  and  cleavage  sections  of  feldspar  are  also  seen. 
Under  the  microscope  it  is  made  up  of  lath-shaped  feldspar 
individuals  and  the  beautiful  groupings  of  augites,  these  set 
out  in  relief  by  the  fine  grains  of  iron  ore  surrounding  them. 
In  the  simplest  cases  the  augite  is  bunched  together  in  long 
parallel  groups,  slightly  diverging  at  the  extremities ;  gener- 


PETROGRAPHY   OF   THE   HAWAIIAN    ISLANDS. 


321 


ally  these  branch  off  at  various  points  into  feather-like  or 
dendritic  forms,  of  such  variety  as  to  be  beyond  description. 
Groups  of  these  forms  radiating  from  a  centre  are  common.^ 


Feather-like  Forms  of  Adgite  :  a  (X  35),^  (X  35),  c  (X  50)  from  Mokuaweoweo, 

d  ( X  70)  from  Kilauea. 

The  accompanying  figure  (1)  shows  several  of  the  more 
complex  of  these  forms  [a,  h,  from  the  same  specimen), 
and  gives  a  fair  representation  of  this  remarkable  structure. 
Fig.  2  gives  the  appearance  of  the  entire  field  of  the  micro- 
scope, showing  forms  like  the  frost  crystals  occasionally  seen 
on  a  stone  pavement ;  this  figure  is  simplified  by  the  omis- 
sion of  some  of  the  less  defined  parts. 

Some  of  the  simpler  rosettes  are  made  up  of  both  feldspar 
and  ang:ite,  alike  radiating-  from  a  common  centre  ;  and  fre- 

^  Mr.  H.  Hensuldt,  of  New  York,  has  called  the  writer's  attention  to  an  angitic 
lava  from  Tahiti,  in  which  a  pinkish,  pleochroic  angite  is  present  in  radiating 
groups  of  acicular  crystals,  often  having  a  nucleus  of  chrysolite.  The  section  is  one 
of  very  exceptional  beauty  and  interest,  although  the  arrangement  of  the  augite  is 
hardly  to  be  compared  with  that  here  described,  since  the  individual  crystals  are 
sharp  and  geometrically  grouped,  —  after  the  manner  of  the  tourmaline  in  luxul- 
lianite,  —  which  is  in  marked  contrast  to  the  feather  forms  of  the  Mount  Loa  augite. 

41 


322 


PETROGRAPHY   OF   THE   HAWAIIAN   ISLANDS. 


quently  the  extremities  of  the  feather  ends  are  feldspar  indi- 
viduals.    Fig.  3  gives  a  detailed  drawing  of  part  of  one  of 


ll/lfi .  i 


Feather-augite  in  Basalt  from  Mokuaweoweo 
(X  60). 


Detailed  Drawing  showing  the 
Feather-like  Grouping  op 
Augite  and  Feldspar  (X  100). 


the  groups.  It  would  seem  that  the  feldspar  was,  as  usual, 
first  separated,  and  the  augite,  as  it  crystallized  out  into  these 
dendritic  forms,  drew  the  feldspar  needles  into  position  with 
it.  The  two  minerals  are  sometimes  so  intricately  involved 
with  each  other  that  it  requires  close  examination  to  sep- 
arate them.  In  polarized  light  the  distinction  comes  out 
more  sharply. 

Occasionally  the  feldspar  is  present  in  larger  forms ;  and 
more  interesting  to  note  is  an  occasional  augite  crystal 
(Fig.  1,  h)  that  evidently  belongs  to  an  earlier  generation, 
and  shows  the  distinct  cleavage,  and  more  or  less  also  the 
crystalline  outline  of  the  species.  The  alteration  to  which 
this  specimen,  with  others  like  it,  has  been  subjected,  and  to 
which  the  red  or  purple  color  of  the  rock  in  the  mass  is 
due,  has  stained  the  iron  red,  and  reddened  also  the  augite, 
although  only  exceptionally  to  such  an  extent  as  to  make  it 
opaque.  The  alteration  spoken  of  may  be  simple  weathering, 
although  the   occasional  brick-red  color  rather  suggests  the 


PETROGKAPHY    OF   THE   HAWAIIAN    ISLANDS.  323 

action  of  hot  water  or  steam ;  the  feldspar  remains  perfectly 
clear  and  unchanged. 

From  the  specimen  described,  which  may  be  taken  as  the 
type,  we  pass  to  the  coarser-grained  kinds  on  the  one  hand 
and  to  the  very  fine-grained  on  the  other ;  both  of  these  still 
retaining,  however,  the  same  general  characters.  A  highly 
cellular  specimen  (No.  74)  with  large  vesicles,  from  the  north- 
west brink  of  the  crater,  departs  in  general  aspect  most 
widely  from  the  type ;  but  wliile  relatively  coarse-grained, 
it  exhibits  the  same  grouping,  though  somewhat  more  rigid 
and  geometrical,  and  shows  even  more  clearly  the  mutual 
relations  of  the  feldspar  and  augite.  In  the  finer-grained 
varieties  the  augite  sometimes  predominates  so  largely  that 
the  whole  becomes  like  a  confused  carpet  pattern  of  in- 
terlacing arabesque  forms,  though  here,  when  an  individual 
form  can  be  traced  out,  it  has  great  beauty  and  perfection, 
branching  and  rebranching  like  some  delicate  forms  of  vege- 
tation. Fig.  1,  c,  is  an  attempt  to  illustrate  one  of  these 
forms,  but  it  lacks  the  delicacy  of  the.  original.  These  forms 
consist  almost  exclusively  of  augite,  with  very  little  feldspar. 
In  another  specimen  of  similar  character  a  partial  fluidal 
structure  was  noticed  in  the  arrangement  of  the  feldspar. 

When  the  iron  grains  are  only  sparingly  present,  and  there 
has  been  no  conspicuous  alteration,  the  rock  is  of  a  light 
uniform  gray ;  but  the  presence  of  iron  in  large  amount 
makes  it  nearly  black  and  obscures  this  structure  ;  and  when 
it  and  the  augite  are  higlily  altered,  the  rock  is  a  bright 
brick-red,  and  in  a  section  appears  as  a  collection  of  nearly 
opaque  red  rosettes,  the  feldspar,  however,  still  remaining 
clear.  Glass  is  present  occasionally,  but  usually  in  insignifi- 
cant amounts,  and  for  the  most  part  it  is  nearly  or  quite 
absent.  This  feather-form  of  augite  which  has  been  de- 
scribed is  not  entirely  confined  to  the  clinkstone-like  vari- 
eties of  lava,  although  eminently  characteristic  of  them.  It 
was  occasionally  noted  more  or  less  distinctly  in  some  other 


324  PETROGRAPHY   OF  THE   HAWAIIAN   ISLANDS. 

forms,  especially  the  vesicular  kinds  to  be  mentioned  later 

4 

(p.  329),  where  it  is  seen  in  the  minute  second-generation 
augite  which  formed  in  the  last  process  of  consolidation.  All 
the  facts  observed  serve  to  connect  its  formation  with  rapid 
cooling. 

Chrysolitic  Basalt.  —  The  second  group  of  rocks  makes  a 
very  marked  contrast  with  those  just  described.  These  are 
of  coarse  grain,  often  open-cellular,  and  very  highly  chryso- 
litic ;  on  this  account  the  specific  gravity  is  much  higher,  it 
varying  from  3'00  to  3*20.^  In  many  cases  they  have  suf- 
fered some  alteration  which  has  given  them  a  dull  waxy  sur- 
face, while  the  large  grains  of  chrysolite  are  frequently 
iridescent,  and  sometimes  have  an  almost  metallic  lustre. 
The  color  varies  with  the  amount  of  iron-oxidation  from 
light  gray  to  dull  reddish  gray  or  brown.  The  mineral  con- 
stituents present  are  those  of  normal  basalt  ;  and  most  prom- 
inent among  these  is  the  chrysolite ;  in  some  specimens  it 
must  make  up  nearly  half  the  mass  of  the  rock  ;  and  in 
one  case  probably  more,  this  particular  specimen  having 
the  unusual  specific  gravity  of  3-20.  The  chrysolite  was 
evidently  early  separated  from  the  magma,  and  the  changes 
of  condition  through  which  the  lavas  have  passed  is  well 
shown  in  the  irregularly  corroded  or  occasional  broken  form 
of  many  of  the  crystals  and  grains.  Even  when  there  is  a 
distinct  crystalline  outline  it  is  not  a  rare  thing  to  find  the 
crystal  broken  and  the  parts  slightly  separated.  This  is 
shown  in  the  accompanying  figures  (4,  a  to/).  Some  of  the 
corroded  forms  take  very  fantastic  shapes.  A  novel  and 
common  feature  of  this  chrysolite  is  the  occurrence  of  very 
slender  acicular  forms.  The  length  is  often  considerable, 
even  when  viewed  microscopically,  —  in  one  case  two  to  three 
millimetres,  —  but  in  breadth  they  are  often  hardly  more  than 
a  line  (note  Fig.  4,  a).     This  chrysolite  shows  the  partial 

1  Some  of  the  separate  determinations  gave  3-09,  3-18,  3-09,  3-04,  3-00,  3-20, 
300. 


PETROGRAPHY   OF    THE    HAWAHAN   ISLANDS. 


325 


alteration  alluded  to  in  a  broad  rim  of  brown  iron  oxide ;  we 
can  pa«s  in  the  same  slide  from  a  crystal  still  preserving  its 


Chrysolite  in  part  with  orientated  titanic  iron;  a-f  (X  55-60),  from  crystalline 
basalts  of  Mokuaweoweo;  g  (X  lb)  from  basaltic  glass,  Mokuaweoweo;  A  (X  60) 
fron,  Nanawale;  ;.  (X60),  Kiiauea ;  /  (XlOO),  crystal  enclosing  glass.  Kilauea ;' 
rn  (X  60)  forked  form,  Maui;  „  (X  60),  portions  of  crystal  enveloped  by  augite  and 
clusters  of  magnetite  grains,  Maui. 

transparency  throughout   to    those   where   only  a   string   of 
chrysolite  grains  marks  the  position  of  the  original  individ- 


326  PETROGRAPHY   OF   THE   HAWAHAN   ISLANDS. 

ual,  and  from  these  to  the  cases  where  a  narrow  brown  line 
of  iron  oxide  alone  is  left ;  in  a  few  cases  the  chrysolite  is 
stained  bright  red,  showing  that  there  has  been  oxidation  of 
the  iron  without  h3'dration. 

The  orientation  of  these  peculiar  rod-like  forms,  which  are 
distinctly  visible  on  a  polished  surface  of  the  rock,  is  a  mat- 
ter of  some  interest.  The  fact  that  in  such  a  form  as  that  of 
Fig.  4,  h,  and  others  like  it,  the  plane  of  the  optic  axes  is 
transverse  to  the  longitudinal  direction  and  the  bisectrix  nor- 
mal to  the  surface  presented,  shows  that  they  are  elongated 
in  the  direction  of  the  vertical  axis,  the  narrow  dimension 
being  that  of  the  macrodiagonal.  This  chrysolite  has  often 
an  unusually  deep  green  color,  possibly  connected  with  the 
partial  alteration,  and  then  shows  distinct  pleochroism  with 
the  absorption  least  in  the  direction  of  the  vertical  axis.  It 
often  shows  spherical  inclusions  of  a  pale  brown  glass,  some- 
times arranged  in  parallel  lines. 

The  plagioclase  feldspar  is  present  in  the  ordinary  forms, 
and  shows  no  unusual  features.  The  augite  forms  irregular 
grains  crowded  among  the  feldspars.  Occasionally  augite  in 
larger  more  distinctly  cr^^stallized  forms  appears,  evidently 
belonging  to  an  earlier  generation.  This  earlier  augite  shows 
the  tendency,  often  observed,  to  cluster  about  the  chrysolite 
grains.  The  titanic  iron  is  not  as  a  rule  abundant,  and  for  the 
most  part  appears  in  long  slender  rods,  often  parallel  among 
themselves  over  a  limited  area,  and  sometimes  orientated  by 
the  chrysolite.  In  two  or  three  of  the  specimens  of  this  class 
the  augite  shows  a  tendency  to  assume  the  radiating  form  ; 
but  this  is  the  exception.  Apatite  is  probably  present  in  some 
sections,  but  only  in  small  amount,  and  in  most  cases  it  was 
not  detected.    Glass  is  almost  entirely  absent  from  these  rocks. 

The  occasional  fractured  character  of  the  chrysolite  has 
been  spoken  of  ;  one  specimen  shows  this  in  an  extreme  de- 
gree, the  chrysolite  being  separated  here  into  many  angular 
fragments,  for  the  most  part  showing  no  crystalline  outline. 


PETROGRAPHY   OF   THE    HAWAIIAN   ISLANDS.  327 

The  feldspar  and  augite  individuals  have  also  suffered  in  the 
same  way,  and  the  ground  mass  has  a  curiously  mottled 
microcrj'^stalline  structure  suggestive  of  some  porphyry.  This 
specimen  stands  comparatively  alone,  although  two  or  three 
others  are  of  somewhat  similar  character. 

The  lavas  of  the  svnnmit  containing  the  most  chrysolite 
were  obtained,  Mr.  Baker  states,  from  tlie  southern  border  of 
the  crater. 

Lavas  with  minute  Crystals  of  Feldspar  and  Augite  in  their 
Cavities.  —  Allied  to  this  second  class  of  rocks  just  described 
are  a  number  of  specimens  which  are  interesting  because  of 
their  remarkable  crystalline  structure.  One  of  these  is  a 
light  gray  rock,  with  only  occasional  vesicles.  It  is,  how- 
ever, throughout  open  and  porous,  v^itli  minute  cavities  into 
w^hich  project  thin  tabular  crystals  of  feldspar  seen  distinctly 
with  a  strong  hand-glass.  A  light  yellowish  augite  is  also 
observed,  but  the  crystals  are  less  distinct.  Iridescent  grains 
of  chrysolite  are  scattered  through  the  mass,  and  the  frac- 
tured surface  shows  the  same  long  lines  of  this  mineral  that 
are  seen  in  the  sections. 

An  interesting  feature  of  this  specimen  and  of  others  like 
it  (including  one  very  similar  collected  two  or  three  hundred 
feet  below  the  summit  of  the  wall  making  the  east-northeast 
side  of  Kilauea,  called  Waldron's  Ledge,  also  others  from 
Makaopuhi)  is  the  presence  in  cavities  of  a  mineral  of  a  milk- 
white  color  in  very  minute  nearly  spherical  forms.  These 
are  rather  abundant  through  the  mass  of  the  rock,  each  little 
cavity  containing  one  or  two  of  them.  They  are  so  small 
(rarely  more  than  -2  or  -o"'"'-  in  diameter)  that  it  is  very  diffi- 
cult to  determine  their  form,  especially  as  the  crystalline 
faces  are  dull  and  give  almost  no  reflections.  A  hexagonal 
outline  can  usually  be  made  out,  and  occasionally  a  triangular 
face  through  which  the  angle  of  another  crystal  sometimes 
projects,  as  if  they  were  complex  penetration  twins,  which  the 
nearly  spherical  form  also  suggests.     Only  one  of  these  forms 


328  PETROGKAPHY   OF   THE   HAWAIIAN   ISLANDS. 

was  detected  in  the  thin  sections,  and  the  free  side  of  this  had 
a  hexagonal  outline,  the  whole  being  divided  into  sectors  which 
alternately  had  like  extinction,  the  surface  of  the  sector  being 
mottled  in  polarized  light  after  the  manner  of  some  crystals 
showing  anomalous  optical  double  refraction.  The  fact  that 
these  little  white  spheres  occur  also  on  the  inner  glazed  sur- 
face of  the  vesicles  would  seem  to  mark  them  of  subsequent 
origin,  and  hence  probably  zeolitic.  Their  form  suggests  a 
rhomboliedral  zeolite  grouped  like  phacolite  or  the  Australian 
herschelite.  Two  or  three  other  zeolitic  minerals  were  ob- 
served in  isolated  cases,  but  too  sparingly  and  in  too  minute 
forms  to  be  satisfactorily  identified. 

In  other  specimens  of  this  class  the  color  is  somewhat 
darkened  because  of  slight  alteration,  the  texture  is  coarser, 
and  the  cavities  larger.  Here  the  clear  glassy  feldspar  tab- 
lets are  very  distinct ;  and  augite  crystals,  red  or  brown  on 
the  surface  and  opaque,  also  project  into  the  cavities.  Octa- 
hedrons of  magnetite  are  often  seen  implanted  upon  the 
augite  needles  ;  and  bi'oad  plates  of  titanic  iron,  with  rhom- 
bohedral  planes  on  the  edges,  sometimes  attain  a  relatively 
large  size.  The  feldspar  tablets  were  here  large  enough  to 
allow  of  their  being  separated  and  examined  optically.  In 
form  they  are  either  rhombic  or  acute  triangular  in  outline,  be- 
ing bounded  by  the  planes  c  (001)  and  y  (201)  ore  and;i;  (TOl), 
with  the  prisms  very  small  when  present  at  all.  They  can 
often  be  seen  to  be  twins  in  accordance  with  the  usual  albite 
law.  The  extinction  on  the  clinopinacoid  made  an  angle  of 
— 14°  to  — 15°  with  the  basal  edge,  which  conforms  to  typi- 
cal labradorite,  as  might  have  been  anticipated.  These 
highly  crystalline  specimens  are  also  much  like  some  of  those 
collected  from  ejected  masses  about  Kilauea,  and  they  may 
here  have  had  a  similar  origin. 

All  the  specimens  that  have  been  thus  far  described 
were  obtained  with  a  single  exception  (No.  74,  already 
located)  either  from  the  talus  in  the  southern  crater  against 


I'ETROcaiAPHY   OF   THE    HAWAIIAN    ISLANDS.  329 

the  wall  of  the  neck  that  joins  it  with  the  central  pit,  or  else 
from  the  east  side  of  the  interior  of  central  Mokuaw^eoweo. 
Nothing  can  be  said  in  regard  to  the  relations  in  place  of  the 
two  types  of  basalt,  which  have  been  described,  and  which 
occur  together  at  the  points  mentioned. 

Other  Varieties  of  the  Lavas.  —  A  number  of  the  specimens 
cannot  be  classed  in  either  of  these  two  groups.  They  are 
light  gray  in  color,  not  vesicular,  and  sparingly  provided 
with  chrysolite,  if  it  is  present  at  all,  and  characterized  by  a 
very  uniform  granular  mixture  of  augite  and  plagioclase.  A 
specimen  taken  from  a  vein  in  the  western  wall  belongs  here, 
also  another  stated  to  have  come  from  the  highest  point  on 
the  edge  of  the  crater.  Still  another  specimen  from  the 
north  brink  is  similar,  but  is  porphyritic  with  patches  of  a 
glassy  plagioclase. 

Another  group  of  specimens,  differing  in  aspect  widely  from 
those  described,  although  not  essentially  so  in  composition, 
are  the  highly  vesicular  kinds,  sometimes  coarsely  vesicular, 
and  again  w^ith  very  minute  cavities.  They  have  for  the 
most  part  a  common  character.  Large  grains  of  chrysolite 
are  usually  present,  often  very  large  in  comparison  with  the 
size  of  the  vesicles  themselves,  and  w^ith  these  also  are  some- 
times large  crystals  of  augite  and  feldspar,  often  grouped 
together.  The  ground-mass  filling  up  the  space  between 
these  first  separated  constituents  is  a  dark  fine-grained  mass 
of  plagioclase  and  augite  with  minute  grains  of  iron  some- 
times so  abundant  as  to  render  the  whole  nearly  black  and 
opaque.  The  augite  sometimes  shows  a  tendency  to  group 
itself  in  the  radiating  forms  already  described.  A  fluidal 
arrangement  of  the  feldspar  is  the  exception,  though  occasion- 
ally observed  in  indistinct  form.  Only  in  rare  cases  is  the 
whole  mass  of  the  rock  made  up  of  this  fine-grained  mass 
without  the  large  crystals.  A  specimen  from  the  source  of 
the  1843  flow  belongs  here. 

A  specimen  wdiich  is  described  as  the  '•  ordinar}^  ancient 

42 


330  PETROGRAPHY   OF   THE   HAWAIIAN   ISLANDS. 

lava  of  the  eastern  brink  of  the  crater''  is  a  dark-colored, 
coarsely  vesicular  rock  (G.  =  3-00),  with  chrysolite  abundant 
in  large  grains,  and  augite  and  feldspar  also  in  large  indi- 
viduals ;  the  amount  of  the  fine-grained  dark  base  of  later 
formation  is  relatively  small,  and  the  augite  is  somewhat 
radiated.  A  peculiar  feature  of  the  section  is  the  inclusion 
by  the  augite  of  large  plagioclase  individuals  not  regularly 
orientated,  and  giving  the  whole  augite  a  peculiar  mottled 
appearance. 

Specimens  of  Glass.  —  The  Mount  Loa  collection  includes 
a  large  number  of  specimens  of  the  scoria,  many  pumice-like 
specimens,  some  of  them  of  extreme  lightness,  and  also  speci- 
mens of  glass.  Several  of  the  glassy  kinds  were  exau^ined 
microscopically.  One  of  them  was  a  dense  black  com- 
pact mass,  uniformly  glassy  on  one  side,  but  on  the  other 
largely  devitrified ;  the  smooth  surface  of  the  glass  was 
roughened  by  minute  projections  due  to  the  chrysolite  crys- 
tals. Its  specific  gravity  is  2-01.  Under  the  microscope  the 
glass  had  a  uniform  brown  color  and  amorphous  character, 
except  for  numerous  minute  doubly  refracting  points  scat- 
tered through  it.  Here  and  there  were  clusters  of  small 
chrysolite  crystals,  having  sharp  outlines,  and  perfectly  clear 
except  for  occasional  inclusions  of  the  glass  and  minute  black 
iron  crystals. 

A  section  cut  transversely  showed  with  great  beauty  the 
gradual  transition  from  the  amorphous  glass  to  the  largely 
devitrified  lava.  The  pale  yellow-brown  glass  of  the  border 
contained  here  and  there  elongated  microlites,  of  dark  Ijrown 
color,  due  to  the  glass  immediately  surrounding  them,  and 
also  minute  crystallites  like  those  described  below.  In  the 
intermediate  zone  the  microlites  were  more  numerous,  and 
were  surrounded  by  a  brown  oval  aureole  of  somewhat  deeper 
color  than  the  rest  of  the  glass,  this  having  a  beautiful 
spherulitic  structure  in  polarized  light.  The  nucleus  was 
sometimes  transparent  (feldspar),  and  about  this  were  curious 


PETROGRAPHY   OF   THE   HAWAHAN   ISLANDS. 


331 


dark  brown  processes  thrown  off  in  curved  lines  (see  Fig.  5). 
The  highly  devitrified  portion  consisted  of  a  nearly  continu- 
ous mass  of  dark   brown  spherulites,   and   crowded    among 


5.  Feldspar  Microlite  surrounded  by  dark  filaments  within  an  oval  of  brown 
glass  (X  90). 

6.  Crystallites  of  various  Forms  (X  160).  All  from  basaltic  glass,  Mokua- 
weoweo. 

them  numbers  of  whitish  nearly  opaque  crystallites.  Many 
of  the  spherulites  have  a  distinct  nucleus  of  chrysolite  or 
feldspar,  and  sometimes  there  is  a  medusa-like  mass  of  dark 
brown  bands  radiating  out  from  the  nucleus. 

The  crystallites  (see  Fig.  6)  have  sometimes  a  simple  oval 
form.,  with  a  faintly  indicated  structure  transverse  to  the  longi- 
tudinal axis ;  there  are  also  compound  forms  with  axes  cross- 
ing at  90'',  making  a  four-rayed  star  (6),  or  at  60^,  and  these 
last  when  repeatTed  making  a  regular  six-rayed  star  (c). 
Rarely  these  forms  are  resolved  into  a  delicate  skeleton 
form  of  the  types  indicated  in  d,  e,  f,  and  of  many  other 
less  regular  shapes.  Similar  forms  of  "  crystalloids "  are 
figured  by  Vogelsang  in  Plate  VII.  of  his  work  ''  Die 
Krystalliten." 

Chrysolite  is  distributed  through  the  section  in  isolated 
crystals  or  in  clusters.  These  crystals  often  enclose  a  con- 
siderable amount  of  the  brown  glass,  and,  while  sharp  in 
outline,  have  sometimes  peculiar  forms  (Fig.  4,  g),  which  are 


332  PETROGRAPHY   OF   THE   HAWAIIAN    ISLANDS. 

interesting  in  connection  with  the  corroded  forms  met  with 
in  the  highly  crystalhne  basalts  which  have  already  been 
described.  Feldspar  is  present  in  the  more  highly  devit- 
rified  portion ;  aiigite  not  distinctly,  except  as  some  of  the 
microlites  are  to  be  referred  to  it. 

Another  specimen  was  lithoidal  in  character,  and  showed 
thronghout  a  distinct  spherulitic  structure.  The  nearly 
opaque  spherulitic  ground-mass  contained  many  light  brown 
transparent  spherulites,  and  grains  of  chrysolite  were  scat- 
tered through  as  in  the  other. 

Lava-streams  from.  Mount  Loa. — A  considerable  number 
of  specimens  are  at  hand  from  the  streams  of  Mount  Loa  of 
different  dates,  and  taken  from  points  at  various  altitudes. 
For  the  most  part  they  are  simply  the  surface  scoriaceous 
portions,  and  consequently  without  distinctive  features.  The 
flows  of  1852,  1855-1856,  1859,  are  thus  represented.  There 
are  also  specimens  of  the  normal  crystallized  lavas  of  the 
stream  of  1880-1881  at  Hilo  ;  of  that  of  1843  taken  from 
near  its  source,  which  has  been  already  alluded  to  ;  and 
of  1868  and  1887.  These  are  all  dark-colored  chrysolitic 
lavas,  vesicular  in  a  high  degree,  especially  that  from  near 
Hilo  (1881),  and  their  characters  are  those  of  the  vesi- 
cular forms  spoken  of  on  page  329.  The  specimens  of 
the  flows  of  1868  are  to  be  mentioned  as  particularly  rich 
in  chrysolite. 

Lava-stalactites  from  Caverns  in  Mount  Loa 
Lava-streams. 

Perhaps  the  most  interesting  and  remarkable  formations 
connected  with  the  lava-flows  from  Mount  Loa  are  the  deli- 
cate stalactites  and  stalagmites  of  lava  which  occur  in  the 
caverns.  The  specimens  in  the  collection  are  mostly  from  a 
cavern  in  the  lava-stream  of  1881  near  Hilo,  as  described  on 
page  209.     Figures  of  some  of  the  forms  of  similar  stalactites 


Plate  XV. 


Stalactites  from  L 


AVA-CAVERNS    NEAR    IIlLO    (J). 


PETROGRAPHY   OF   THE   HAWAIIAN   ISLANDS.  335 

from  the  caverns  of  Kilauea  are  given  by  Brigliam,  as  more 
particularly  mentioned  later. 

According  to  the  accounts  given,  the  flowing  lava-stream, 
crusted  over  at  the  surface,  leaves  behind  it,  when  the  molten 
material  has  flowed  by,  long  caverns,  usually  five  to  ten 
feet  in  height,  having  a  roof  of  one  to  three  or  more  feet  in 
thickness  and  a  floor  of  the  solidified  lava.  In  the  caverns 
are  found  hanging  from  the  roof  the  slender  lava-stalactites. 
In  the  Hilo  cavern  they  were  from  a  few  inches  to  twenty  or 
thirty  in  length,  and  in  some  places  only  six  to  eight  inches 
apart.  The  diameter,  which  seems  to  have  been  determined 
by  the  size  of  the  drop  of  the  liquid  material,  does  not  vary 
much,  Ijeing  usually  about  a  quarter  of  an  inch.  Beneath  the 
stalactites,  from  the  floor  below,  rise  the  clustered  groups  of 
the  stalagmites.  These  delicate  forms  are  so  fragile  that  they 
hardly  bear  transportation,  and  it  is  consequently  difficult 
to  preserve  the  longer  specimens  in  their  original  form. 
Through  the  kindness  of  Mr.  Baker  the  writer  has  received 
an  admirable  series  of  them,  part  of  which  are  shown,  one 
third  of  the  natural  size,  on  the  accompanying  plate.  These 
specimens  were  collected  with  great  care  and  skilfully  packed 
in  moss,  and  although  fractured  at  many  points  when  they 
arrived  in  New  Haven,  and  thus  divided  into  sections  an 
inch  or  two  in  length,  it  was  found  possible  to  cement  them 
together  in  their  original  positions. 

The  general  aspect  of  the  stalactites  and  stalagmites  is  so 
well  shown  in  the  series  of  figures  on  Plate  XV.  that  but  little 
description  is  needed.  It  will  be  noticed  that  while  some  are 
straight  and  nearly  uniform,  others  are  curiously  gnarled  and 
knotted,  especially  near  their  lower  extremities.  The  end  has 
often  a  little  process  thrown  off  at  right  angles,  a  little  hook, 
or  a  close  spiral  of  two  or  three  turns,  often  tangled  or  knotted 
together.  The  simple  rods  are  usually  round,  not  often  flat- 
tened except  when  there  is  a  sudden  change  in  direction, 
when  they  may  l)e  pinched  together  like  a  glass  tube  bent 


336 


PETROGRAPHY  OF   THE   HAWAIIAN   ISLANDS. 


when  hot.  The  surface  is  exquisitely  ornamented  with  most 
delicate  markings.  The  stalagmites,  formed  by  the  drop- 
pings from  above,  are  intricate  clusters  or  piles  of  simple 
drops  several  inches  in  height,  as  well  represented  in  Figures 
a  and  h  on  the  plate. 

The  exterior  of  the  stalactites  has  usually  a  more  or  less 
bright  metallic  lustre,  and,  though  sometimes  dull  and  fine 
granular,  the  surface  often  reflects  the  light  brilliantly  from 
a  multitude  of  crystalline  facets  ;  these  sometimes  separate 
into  distinct  scales,  shown  to  be  largely  hematite  by  their 
reddish  streak,  though  magnetite  is  also  present.  Minute 
rounded  crystals,  apparently  also  of  hematite,  are  sprinkled, 
often  thickly,  over  the  surface.  Sometimes  the  metallic 
covering  is  very  thin,  or  is  not  continuous,  forming  patches 
on  a  brown  surface  ;  occasionally  at  the  ends  it  is  altogether 
absent,  and  the  exterior  is  thus  brown  and  glassy  in  aspect, 
7  but    still    retains    the 

polyhedral  crystalline 
aspect ;  this  glass-like 
crust  polarizes  light, 
and  is  probably  augite. 
^  ^  ^  Over  portions  of  the  rods 

li'.Li^   "^^^^"""^P     ^^    I    '~^^1  — '^^^  i^  ^^1^  c^®6  of  the 

straight  uniform  ones 
(see  the  plate)  over  the 
whole  length  —  tlie  sur- 
face  is  transversely 
ribbed  or  corded  in  the 
most  delicate  manner. 
The  beauty  and  perfec- 
tion of  these  little  ripple- 
marks,   as  seen  under  a 

Lava-stalactites  (X  f). 

hand-glass,  are  beyond 
description  or  adequate  representation.  They  are  parallel 
and  symmetrical  for  a  limited  distance,  but  vary  in  fineness 


PETROGRAPHY   OF   THE   HAWAUAN   ISLANDS. 


and  form  with  every  change  in  direction  of  the  stalactite 
itself.  Their  flow  is  especially  varied  abont  each  little 
projecting  knob.  Fig.  7  will  give  some  idea  of  the  trans- 
verse markings,  bnt  details  of  the  structure  can  hardly  be 
reproduced. 

The  straighter  portions  of  the  stalactites  are  often  solid 
throughout,  though  here  and  there  they  are  hollow  and  con- 
sist of  a  mere  shell.  Often  portions  that  are  perfectly  solid 
alternate  with  the  cellular  parts,  or  the  solid  parts  contain 
a  series  of  large  vesicles.  Fig.  8  gives  longitudinal  cross 
sections  through  a  number  of  typical  forms.  In/  the  lower 
cavity  was  thickly  lined  with  crystals  chiefly  of  feldspar.  The 
exterior  crust  is  seen  in  the  cross  section  under  the  microscope 
to  be  very  thin,  and  next  to  it  comes  usually  a  narrow  but  not 
always  continuous  band  of  augite,  with  occasional  iron  crys- 
tals. The  solid  parts 
contain  within  very 
slender  lath-shaped 
feldspars  of  a  con- 
siderable relative 
length,  often  from 
one  quarter  to  one 
eighth  of  the  diam- 
eter of  the  stalac- 
tite, as  seen  in  a 
longitudinal  section. 
In  one  case  they 
showed  a  marked 
tendency  to  paral- 
lelism with  the  axis 
of  the  stalactite,  but 
in  other  cases  this  was  less  distinct.  A  partial  concentric 
arrangement  as  seen  in  a  transverse  section  was  also  noted. 
The  feldspars  often  have  black  longitudinal  inclusions, 
probably  of  magnetite  ;    and   their  cross  sections,  square  or 

43 


Longitudinal  Sections  of  Lava-stalactites  in 
outline  (X  f),  showinfi  open  and  solid  portions,  a  solid 
and  d  open  throughout,  d  with  crystalline  lining ;  the 
lower  part  of  /  is  thickly  lined  with  crystals,  chiefly 
feldspar. 


338 


PETROGRAPHY  OF   THE   HAWAIIAN   ISLANDS. 


Sections    of    L.vva-stalactites    (X  o) 
a  longitudinal,  b  transverse  (X  5). 


rectangular  in  outline,  then  have  a  large  black  centre  of  the 
same  form.  A  rather  deeply  colored  greenish  yellow  augite, 
somewhat  pleochroic,  is  packed  in  among  the  feldspars, 
and  occasionally  shows  sharp  crystalline  outlines.  There 
are  also  numerous  grains  and  octahedrons  of  magnetite, 
9  and  throughout  a  multitude 

of  beautiful  dendritic  forms 
branching  at  angles  of  90° 
or  of  60°.  This  is  one  of 
the  most  marked  characters 
of  the  sections.  The  areas, 
where  these  iron  dendrites 
are  crowded  together,  are 
less  distinctly  individual- 
ized, but  no  glass  was  noted.  Chrysolite  is  also  absent. 
Fig.  9  (a  and  h)  will  convey  some  idea  of  the  appearance  of 
the  longitudinal  and  transverse  sections.  The  fact  that  the 
structure  is  throughout  coarsely  crystalline  with  the  normal 
constituents  of  the  basalt  —  except  the  chrysolite  —  is  an 
important  point. 

The  occasional  cavities  or  open  spaces  in  the  solid  parts  of 
the  stalactites  are  often  beautifully  lined  with  large  rhombic 
tables  of  feldspar,  perfectly  clear,  and  so  excessively  thin  as 
to  suggest  scales  of  mica  ;  also  dark  needles  of  augite,  often 
curved  and  wire-like  ;  and  octahedrons  of  magnetite.  (See  Fig. 
8,/.)  The  feldspar  plates  have  mostly  the  form  of  a  symmet- 
rical lozenge  (Fig.  10),  with  angles  of  128°  and  52° ;  one  side 
is  shown  by  the  clea.vage  to  be 
bounded  by  the  basal  plane,  the 
other  by  the  dome  x  (TOl).  The 
extinction  makes  an  angle  of  —  7° 
to  —  9°  with  the  basal  edge,  which 
conforms  to  that  of  andesine  ;  that 

is,  a  plagioclase  somewhat  more  acidic  than  that  determined 
in  the  rock  mass.     These  feldspar  plates  are  often  marked  on 


PETROGRAPHY   OF   THE   HAWAHAN   ISLANDS.  339 

the  edges  with  a  thin  black  scale,  presumably  magnetite,  with 
numerous  minute  circular  open  spaces  containing  many  black 
points,  as  if  the  whole  were  formed  by  the  drying  of  little 
bubbles.  The  augite  crystals  are  often  rough,  and  black  witli 
magnetite. 

Where  there  are  vesicular  cavities,  often  filling  the  whole 
interior  of  the  tube,  these  are  lined  with  a  comparatively 
smooth,  shining  web  of  feldspar  plates  and  clusters  of  brown 
augite  crystals,  or  of  augite  needles  alone,  woven  together 
like  basket-work.  The  dull  surfaces  of  magnetite  octahe- 
drons are  scattered  abundantly  among  the  augite  and  feld- 
spar. The  large  quantit}^  of  magnetite  is  shown  by  the  fact 
that  the  magnet  picks  up  many  of  the  fragments  of  the 
stalactites,  even  when  quite  large.  The  specific  gravity  of 
fragments  of  the  solid  portion  of  a  stalactite  was  found  to 
be  2-98. 

The  explanation  of  the  process  by  which  these  unique  vol- 
canic icicles  have  been  formed  is  not  easy  to  give.  It  is  clear 
that  further  study,  on  the  spot,  of  their  occurrence  and  the  cir- 
cumstances of  their  growth  is  called  for.  It  seems  at  first 
most  easy  to  think  of  them  as  made  by  the  rather  rapid  drip- 
ping of  the  semi-viscid  lava  from  the  roof.  The  evidence  at 
hand,  however,  shows  pretty  conclusively  that  they  could  not 
have  been  the  result  of  simple  direct  fusion.  The  fact  that 
they  hang  down  from  the  solid  crust,  while  the  stalagmites 
formed  by  the  dripping  from  above  rise  from  the  solid  floor 
beneath,  seems  to  prove  that  they  were  formed  after  the 
molten  lava  had  passed  by  and  the  temperature  had  fallen 
below  the  point  of  fusion.  If  made  directly  from  molten 
material,  they  could  hardly  be  so  perfectly  crystalline 
throughout  as  they  have  been  shown  to  be  ;  we  should  ex- 
pect to  find  them  more  like  the  glassy  spatterings  from  the 
blow-holes  of  Kilauea  mentioned  on  a  later  page.  Moreover, 
the  sorting  out  of  the  material  is  further  evidence  on  the 
same  side,  —  the  crystalline  shell  of  hematite  and  magnetite, 


340  PETROGRAPHY   OF   THE   HAWAIIAN   ISLANDS. 

with  its  lining  of  augite,  and  within  the  solid  crystalline 
mass,  or  the  clusters  of  beautiful  crystals  chiefly  of  feldspar. 
Still  again,  the  question  has  been  raised  as  to  whether  the 
flow  of  a  viscid  liquid  like  the  molten  lava  could  form  drops 
so  small  as  the  size  of  the  stalactites  shows  must  have  been 
present. 

The  fact  that  the  lava  rods  or  tubes  of  the  stalactites  are 
of  nearly  uniform  size  throughout  their  length,  although 
bunched  and  knotted  together  at  frequent  points  as  has 
been  described,  is  an  important  one.^  It  separates  them,  as 
to  mode  of  origin,  from  the  stalactites  of  a  limestone  cavern, 
which  form  in  a  more  or  less  conical  shape  from  the  flow 
down  over  the  exterior  surface  of  the  lime-bearing  solution. 
It  seems  to  require  that  the  shell  should  have  formed  first, 
and  that  these  tubes  should  have  lengthened  by  the  material 
carried  down  within  them,  finally  resulting  in  their  becoming 
solid  to  a  greater  or  less  extent.  This  is  confirmed  by  the 
fact  that  the  parts  seemingly  most  solid  often  prove  to  have 
at  the  centre  minute  crystal-lined  cavities.  The  lengthening 
by  the  addition  of  material  at  the  point  of  attachment  above, 
the  only  other  method  that  can  be  suggested,  is  difficult  to 
conceive  of. 

As  the  facts  at  hand  are  inconsistent  with  the  theory  of 
a  direct  formation  from  the  melted  condition,  we  are  forced 
to  speculate  as  to  the  power  of  the  highly  heated  water- 
vapor,  known  to  be  present  in  large  quantities,  to  form  them 
from  the  roof  by  a  sort  of  process  of  aqueo-fusion.  This  is  a 
subject  about  which  we  know  too  little  at  present  to  make 
speculation  very  profitable,  and  the  author  prefers  to  drop  the 
discussion  here  in  the  hope  that  further  observations  may 
throw   important  light  upon  the  matter.     The  experiments 

1  A  stalactite  from  a  Kilauea  cavern  collected  by  Prof.  J.  D.  Dana  is  of  interest 
here,  since  it  forms  an  exception  to  those  that  have  been  described.  Abont  the  first- 
formed  stalactite,  with  its  rather  thick  magnetite  shell  has  been  formed  a  second, 
somewhat  vesicular  and  nearly  concentric  with  it.  This  stalactite  has  the  exterior 
coating  of  gypsum  crystals  spoken  of  by  Brigham. 


PETROGRAPHY  OF   THE   HAWAIIAN   ISLANDS.  341 

of  Fouque  and  Levy  in  regcard  to  the  formation  of  basalt 
with  their  important  results,  pursued  the  method  of  simple 
igneous  fusion;  and  though  Daubree  has  discussed  the  role 
of  water  in  the  formation  of  basalt  and  basaltic  minerals, 
the  investigations  thus  far  made  hardly  seem  to  apply  very 
closely  to  the  present  case. 

The  fact  that  these  stalactites  occur  also  in  the  caverns 
of  Kilauea  has  already  been  mentioned.  Brigham  describes 
them  at  some  length  ;  and  although  it  is  hardly  possible  to 
accept  all  his  statements  literally,  especially  as  to  rate 
and  conditions  of  growth,  his  remarks  are  quoted  here  at 
length  :^  — 

"  A  formation  which  always  excites  the  curiosity  of  visitors  to 
Kilauea  is  found  in  many  of  the  caves  in  the  floor  of  the  crater 
which  have  been  undisturbed  for  several  years.  At  first  glance 
the  tubes  which  hang  from  the  roof  and  the  curiously  formed 
droppings  beneath  these  seem  to  be  of  igneous  origin.  An  exami- 
nation m  situ,  shows  that  this  was  not  the  case.  The  roof  of  these 
caves  is  about  two  feet  thick  and  generally  unbroken  ;  the  stalac- 
tites do  not  occur  under  cracks,  and  indeed  there  is  often  no  fresh 
lava  over  the  surface.  The  formative  process  may  be  clearly  seen 
as  the  tubes  form  from  day  to  day  ;  and  I  have  caught  the  steel- 
gray  deposit  in  the  drops  on  the  end  of  the  tubes  upon  my  finger 
and  watched  its  solidification.  Usually  the  tubes  are  straight  cylin- 
ders from  one  inch  to  three  eighths  of  an  inch  in  diameter,  and  some- 
times more  than  two  feet  long.  The  bore  is  almost  never  continuous  ; 
and  while  externally  they  are  smooth,  within  a  mass  of  stony  cells 
of  considerable  size  is  presented.  As  long  as  these  tubes  grow 
downward  in  the  quiet  upper  region  of  the  cave,  they  hang  perpen- 
dicularly, but  when  they  reach  farther  down  the  currents  of  air  and 
steam  blow  the  deposits  to  one  side  and  the  tube  becomes  distorted ; 
it  may  even  return  on  itself.  The  drip  in  the  bottom  forms  much 
thicker  and  more  irregular  stalagmites,  as  will  be  seen  from  the 
figure,  which  represents  three  actual  forms,  not  occurring,  however, 
in  the  same  cave.  Specimens  have  been  found  which  exceed  eight 
inches  in  diameter,  and  these  are  usually  low  and  fiat-topped.  The 
more  slender  ones  sometimes  rivse  to  a  height  of  two  feet ;  and  so 

1  IvrciiioiT,  ].!>.  4(;-2,  i«:'.. 


342  PETROGRAPHY   OF   THE   HAWAIIAN   ISLANDS. 

rapidly  is  the  silica  deposited  that  they  seldom  increase  in  diameter, 
but  are  true  acrogens,  none  of  the  suspended  silica  running  down  the 
sides.  In  one  cave  the  growth  of  the  stalactites  was  at  about  the 
rate  of  an  inch  a  week,  but  owing  to  the  varying  amount  of  water  or 
steam  the  production  is  quite  irregular.  They  are  often  coated  with 
beautiful  white  crystals  of  gypsum,  sometimes  tipped  with  needle- 
like transparent  crystals  of  the  same  mineral  when  the  cave  is 
high.  The  natives  collect  them  with  the  upper  open  joint  of  a  long 
bambu." 

The  following  analysis  of  the  solid  stalactite,  by  John  C. 
Jackson,  is  given  by  Brigham :  — 

SiOa        AI.2O3       FeoOg       MnO       CaO       MgO      NaoO      KjO 
G.   ==  2-9  51-9  13-4  15-5  08         9-6  48         30  11  =  100-1 


Lavas   of   Kilauea. 

The  specimens  in  hand  from  the  volcano  of  Kilauea,  which 
have  been  examined  microscopically,  include  four  specimens 
of  the  recent  lava  from  the  bottom  of  the  crater,  six  speci- 
mens of  the  older  lavas,  two  from  Waldron's  ledge  on  the 
northeast  side,  and  four  from  the  wall  west  of  Halema'uma'u  ; 
finally,  a  number  from  the  ejected  masses  on  the  borders  of 
the  crater,  especially  on  the  west  side.  There  are  also  a 
number  of  glassy  and  scoriaceous  kinds. 

1.  The  Rece7it  Lavas.  —  The  specimens  of  the  recent  lavas 
were  taken  from  the  stony  part  of  the  layer  below  an  inch 
or  more  of  glassy  crust.  They  are  dark-colored,  vesicular 
basalts,  containing  chrysolite  but  not  in  very  large  amount. 
The  irregular  grains  of  chrysolite  are  often  aggregated  to- 
gether with  augite  crystals,  and  to  a  limited  extent  with  the 
lath-shaped  feldspars  ;  these  constituents  obviously  represent- 
ing those  which  first  separated  from  the  magma.  The  mass 
of  the  solid  portion  of  the  rock  is  of  uniform  character,  con- 
sisting of  augite  and  feldspar,  with  the  interstices  between 
them  black  with  the  crowded  grains  or  plates  of  magnetic 
and  titanic  iron  ;  about  the  borders  of  the  vesicles  the  iron 


PETROGRAPHY  OF   THE   HAWAIIAN   ISLANDS.  343 

is  especially  dense.  It  is  very  interesting  to  note  that  these 
specimens  are  the  only  ones  among  those  from  Kilauea  which 
show  distinctly  the  stellate  feather-like  forms  of  the  augite 
and  feldspar  so  characteristic  of  many  of  the  Mount  Loa 
lavas  (as  shown  in  Fig.  1,  d,  p.  321).  The  augite  forms  here 
are  usually  smaller  and  less  varied,  but  there  is  the  same 
grouping  in  parallel  bundles  diverging  off  at  the  ends  into 
dendritic  forms.  The  association  between  the  augite  and 
feldspar  is  also  very  close,  as  if  the  crystallization  of  the 
two  had  been  almost  sinmltaneous.  Thus  the  feldspar  not 
only  forms  in  some  cases  the  outer  extremities  of  the  feather, 
but  sometimes  also  is  a  central  rib  flanked  on  both  sides  by 
the  augite. 

Occasionally  the  chrysolite  appears  in  the  long  slender 
forms  noted  as  common  amono;  the  Mount  Loa  lavas.     One 

o 

of  these  is  shown  in  Fig.  4,  k,  which  also  exhibits  the  peculiar 
feature  of  many  of  these  rocks,  often  noted  in  other  regions/ 
—  the  grouping  of  the  titanic  iron  in  parallel  position  about 
the  chrysolite,  normal  to  the  vertical  axis.  An  arrangement 
of  the  elongated  forms  of  the  titanic  iron  in  parallel  position 
over  small  areas  is  sometimes  noted  where  there  is  no  evident 
relation  to  the  other  constituents.  Usually,  however,  the 
chrysolite  is  the  controlling  influence,  and  the  individual 
often  bristles  with  these  little  iron  rods  about  its  whole  out- 
line, as  seen  in  the  section.  Although  these  specimens  were 
taken  from  so  near  the  glassy  crust,  there  is  little  or  no  glass 
shown  in  the  thin  section.  A  specimen  from  the  bottom  of 
the  Little  Beggar,  the  lowest  part  of  Kilauea,  shows  very 
considerable  alteration,  the  surface  being  covered,  and  the 
vesicles  filled  with  crystals  of  gypsum  ;  the  mass  is  rendered 
red  and  nearly  opaque  by  the  oxidation  of  the  iron. 

A  specimen  of  partially  devitrified  glass  shows  the  presence 
of  spherulites,  like  those  mentioned  in  similar  specimens  from 
Mount  Loa,  increasing  in  number  where  the  devitrification  is 

1  Of.  Rosenbuscb,  Massige  Gesteine,  1887,  p.  722. 


344  PETROGRAPHY  OF   THE   HAWAIIAN   ISLANDS. 

most  complete.  Crystals  of  chrysolite  and  microlites  of  feld- 
spar are  also  present  in  large  numbers.  Some  curious  speci- 
mens from  the  spatterings  about  a  blow-hole  exhibit  a 
vesicular  glass  with  crystals  of  chrysolite  and  aggregates 
of  augite  and  feldspar.  The  chrysolite  encloses  large 
amounts  of  glass,  often  in  curiously  arranged  S3mimetrical 
bands.     One  of  the  crystals  is  represented  in  Fig.  4,  /. 

2.  The  Older  Lavas.  —  Of  the  ancient  Kilauea  lavas  one 
specimen  from  Waldron's  Ledge  is  remarkable  for  its  highly 
chrysolitic  character,  as  its  unusual  density  (G.  =  3*18)  well 
shows.  It  is  a  grayish  compact  rock,  thickly  sprinkled 
with  greenish  yellow  chrysolite  grains.  Under  the  micro- 
scope the  chrysolite  is  seen  to  be  in  large  individuals,  usually 
irregular  grains,  though  also  in  indistinct  crystals  and  occa- 
sional rod-like  forms.  These  often  contain  abundant  glass 
inclusions.  The  grains  are  often  packed  about  with  a  poorly 
defined  border  of  augite,  and  it  is  in  this  zone  particularly 
that  the  little  rods  of  titanic  iron  are  regularly  orientated, 
standing  out  from  the  chrysolite  in  the  manner  already 
described.  Besides  this,  it  is  a  granular  mixture  of  augite 
and  plagioclase,  not  showing  any  glass.  The  other  specimen 
from  the  foot  of  Waldron's  Ledge,  is  a  light-gray  cellular 
rock,  highly  crystalline,  the  minute  cavities  lined  by  plates 
of  feldspar  and  tables  of  titanic  iron.  It  is  much  like  some 
of  the  specimens  described  from  Mount  Loa  (p.  327),  and 
with  them  is  characterized  by  the  same  milk-white  spherical 
mineral  in  the  cavities,  provisionally  referred  to  phacolite. 

The  lavas  from  the  west  wall  of  Kilauea  west  of  Halema'u- 
ma'u  are  all  closely  similar  in  character  among  themselves  ; 
they  are  dark-gray  in  color,  vesicular,  and  contain  a  fair 
amount  of  chrysolite.  The  structure  is  throughout  crystal- 
line, rather  coarsely  granular,  and  the  chrysolite  is  marked 
by  its  usual  bristling  border  of  titanic  iron.  One  or  two 
of  these  show  something  of  the  radiatino;-  augite  forms. 

3.  Ejected  Masses  on  the  Borders  of  Kilauea.  —  The  speci- 


PETROGRAPHY    OF   THE   HAWAHAN    ISLANDS.  345 

mens  from  tlie  borders  of  Kilauea  are  supposed  to  have  been 
ejected  at  an  explosive  eruption  about  a  century  since.  The 
larger  part  of  the  masses  are  described  by  Prof.  J.  D.  Dana  as 
being  of  a  fine-grained,  gray,  slightly  vesicular  lava.  Other 
specimens  are  reddish  or  chocolate-colored,  coarsely  granular 
and  highly  crystalline.  In  the  latter  the  chrysolite  is  present 
in  very  large  amount,  and  has  suffered  from  alteration, — 
probably  by  the  action  of  heated  water- vapors,  —  so  that  the 
fractured  surface  is  eitlier  dull-red  and  opaque  or  else  slightly 
iridescent.  The  feldspar  crystals  are  clear  and  glassy,  and 
where  there  are  cavities  they  often  project  in  distinct  trans- 
parent plates  from  the  walls.  The  crystals  have  an  angle  of 
extinction  of  — 14°  with  the  h!c  edge,  and  hence  conform  to 
labradorite,  like  those  of  similar  occurrence  among  the  Mount 
Loa  specimens.  Under  the  microscope  the  chrysolite  is  seen 
to  be  surrounded  with  a  deep-red  border,  and  the  iron  oxida- 
tion has  penetrated  into  the  mass  of  the  crystal,  sometimes 
along  broad  fracture-lines,  and  more  generally  in  a  network 
of  fine  wavy  lines,  giving  it  a  peculiar  feathery  aspect.  Not 
infrequently  the  oxidation  has  gone  so  far  that  the  chrysolite 
is  perfectly  opaque,  and  by  reflected  light  is  bright  brick-red. 
Three  specimens  among  the  examples  of  the  light-gray 
lavas  have  peculiar  cliaracters.  One  is  a  light-gray  rock  con- 
spicuous among  all  those  under  examination  for  its  beautiful 
crystalline  structure.  It  is  very  light  and  porous,  and  in 
each  little  cavity  there  are  groups  of  crystals  of  feldspar  in 
the  usual  rhombic  plates,  with  minute  slender  needles  of  a  pale 
yellow  augite  iridescent  on  the  surface,  and  thick  tables  of 
titanic  iron  showing  large  rhombohedral  planes  (cr  =  56°). 
These  last  have  bright  faces,  often  cavernous,  and  with  a 
bluish  steel-like  tarnish.  The  augites  are  flattened  parallel 
to  the  orthopinacoid,  as  shown  by  the  parallel  extinction  and 
the  oblique  optic  axis.  Chrysolite  is  present  in  the  mass  of 
the  rock,  but  hardly  appears  in  the  sections.  Specific  gravity, 
310. 

44 


346  PETROGRAPHY   OF   THE   HAWAIIAN   ISLANDS. 

Another  similar  rock  is  more  compact,  except  for  paral- 
lel lines  of  cavities  partially  filled  with  black  glass.  A  third 
shows  the  same  structure  in  part ;  but  the  mass  of  the  speci- 
men has  a  base  of  a  very  black  glass  with  crystals  of  feldspar, 
augite,  and  broad  plates  of  titanic  iron  running  through  it. 
In  the  large  cavities  the  crystals  of  these  minerals  project 
out,  though  the  surface  of  the  cavity  is  lined  with  a  glassy 
web.  The  specific  gravity  is  3*  15.  One  of  the  sections  under 
examination  is  cut  across  the  junction,  and  shows  both  the 
uniform  fine-grained  crystalline  portion  and  the  glassy  part 
with  its  large  enclosed  crystals.  A  curious  feature  of  the 
glass  is  the  presence  of  a  swarm  of  minute  apatite  needles 
running  through  it  in  every  direction.  These  do  not  extend 
into  the  crystallized  parts.  Apatite  usually  appears  as  one 
of  the  very  earliest  secretions  from  the  magma,  and  why  it 
should  be  thus  localized  in  these  patches  of  glass  while  absent 
from  the  crystalline  parts  of  the  rock  it  is  difficult  to  explain. 
In  general,  apatite  has  been  found  to  be  a  rare  constituent  of 
the  Hawaiian  lavas. 

Two  other  specimens  are  gray  compact  rocks,  extremely 
fine-grained  except  for  occasional  chrysolite  grains.  Another 
is  peculiar  in  having  small  uniformly  distributed  patches  of 
a  dark-colored  slightly  opalescent  glass,  which  is  deep  brown, 
and  nearly  opaque  in  the  thin  section  except  as  it  is  pene- 
trated by  apatite  needles,  which  here  also  are  confined  to  it. 

With  the  specimen  from  Kilauea  proper  belong  those  col- 
lected by  Mr.  Baker  from  Nanawale  and  Makaopuhi,  the 
former  chiefly  remarkable  for  their  chrysolitic  character,  the 
latter  sparingly  so.  Several  of  the  latter  specimens  are  re- 
markable for  that  crystalline  structure  that  has  been  several 
times  remarked  upon,  and  one  of  them  contains  the  white 
zeolitic  mineral. 

Former  observers  have  dwelt  at  length  upon  the  features  of 
the  glassy  forms  of  the  lava  and  the  presence  of  glass  in  the 
partly  crystalline  varieties.     This  is  probably  to  be  explained 


PETROGRAPHY  OF   THE    HAWAIIAN    ISLANDS.  347 

by  the  fact  that  the  specimens  which  first  present  themselves 
to  the  collector  on  his  visit  to  the  interior  of  Kilauea  are  the 
superficial  more  or  less  scoriaceous  or  glassy  forms,  which  con- 
stitute merely  a  crust,  and  do  not  represent  the  true  character 
of  the  average  lavas.  The  writer  has  found  glass  only  a 
comparatively  insignificant  element  in  the  normal  rocks,  and 
often  wholly  absent,  even  from  those  of  recent  eruption. 

Relation  between  the  Rocks  of  the  Summit  Crater  of 
Mount  Loa  and  those  of  Kilauea. 

In  general  the  lavas  of  the  summit  crater  and  of  Kilauea, 
so  far  as  examined  by  the  writer,  are  strikingly  similar  in  char- 
acter, all  being  augitic  basalts,  varying  chiefly  as  regards  the 
amount  of  chrysolite  present.  The  clinkstone-like  rock  of 
Mokuaweoweo  has  not  been  observed  at  Kilauea ;  but  the 
feathery  grouping  of  augite  and  feldspar  which  characterizes 
it  belongs  to  the  recent  Kilauea  lavas  as  well.  The  darker- 
colored  vesicular  basalts,  which  are  highly  chrysolitic,  and 
hence  of  high  specific  gravity,  are  alike  from  both  craters. 
Writers  on  volcanoes  have  attempted  to  draw  conclusions  in 
regard  to  the  distribution  of  the  heavier  and  lighter  lavas 
according  to  altitude,  limiting  the  former  to  the  lower  levels. 
This  is  a  natural  inference  on  a  priori  grounds ;  but  it  does 
not  rest  on  observation,  as  the  facts  already  stated  sufficiently 
show.  It  is  a  striking  fact  in  connection  with  the  mechanics 
of  volcanic  eruptions  that  lavas  of  the  heaviest  character 
(specific  gravity,  3-15  and  3-20)  should  have  been  raised  to 
an  altitude  of  nearly  fourteen  thousand  feet  above  sea-level. 

The  chemical  composition  ^  of  the  Kilauea  lavas  is  well 
shown  by  the  series  of  analyses  (fourteen  in  number)  given 

1  The  remark  made  by  Prof.  J.  D.  Dana  must  be  repeated  here,  that  the  early 
analyses  published  in  the  "  Geological  Report  of  the  United  States  Exploring  Ex- 
pedition," having  been  made  for  him  by  an  inexperienced  analyst,  are  entirely 
unreliable,  and  should  not  be  (quoted. 


348  PETROGRAPHY   OF   THE   HAWAIIAN    ISLANDS. 

by  Silvestri,  and  also  those  —  chiefly  of  glassy  forms  — given 
by  Cohen. 

Of  these  analyses  three  by  8ilvestri  (A,  B,  C)  and  two  by 
Cohen  (D,  E)  are  quoted  here ;  namely, — 

A.  Recent  vitreous  basalt,  fresh  and  unaltered. 

B.  Older  basalt,  also  fresh. 

C.  Older  basalt,  much  altered. 

D.  Compact  basalt-obsidian. 

E.  Pele's  Hair. 

A.  B.  C.  D.  E. 

G.  =  2-97  G.  =  301  G.  =  2-8U  G.  =  2-75  G.  =  2'66 

SiOg 4920  4882  48-00  53-81  5082 

TiOa 1-72  1-16  .  .  .  201  undet. 

AI2O3 14-90  15-22  25-45  13-48  9-14 

FeA 4-51  5-72  1755  302  733 

FeO 12-75  9-65  1-20  7-39  7  03 

MnO 0  28  0-67  tr.  Ir.  0  38 

CaO 9-20  10-40  220  10-34  11-63 

MgO 3-90  4-65  098  646  7-22 

Na.O 1-96  2-10  (  323  1-02 

K2O 0-95  0-90  1  0.64  3-06 

P2O5 042  tr.  tr.  ...  ... 

H2O 010  .  .  .  1  87  057  1-74 

99-89  99-19  99  23  10095  9937 

Of  other  specimens  from  the  island  of  Hawaii  there  are 
two  specimens  from  Pimaluu,  on  the  southern  coast,  —  one 
from  the  outside  of  a  bomb  and  the  other  from  an  aa  flow. 
The  interesting  point  about  these  is  the  strongly  accentuated 
flow- structure  as  shown  in  the  feldspar  microlites  as  they  find 
their  way  around  the  occasional  large  crystals  of  chrysolite 
and  augite.  The  fluidal  character  is  as  a  rule  entirely  absent 
from  the  specimens  before  described,  and  in  general  is  not  so 
common  in  basic  as  in  acidic  lavas. 

Specimens  from  western  and  northwestern  Hawaii,  Kawai- 
hae,  and  Mahukono  are  again  more  or  less  vesicular  chryso- 
litic  basalts.  Of  these  rocks  that  from  Kawaihae  is  the  most 
noteworthy  because  of  the  large  clusters  of  glassy  feldspar 
cryst;ils,   which  give  it  a  striking  porphyritic  aspect. 


PETROGRAPHY  OF  THE   HAWAHAN   ISLANDS.  349 


Lavas  of  Maui. 

From  the  island  of  Maui  about  a  dozen  specimens  have 
been  subjected  to  microscopical  examination,  of  which  three 
were  collected  by  Rev.  S.  E.  Bishop.  The  most  recent  lavas 
of  Haleakala  are  represented  by  three  specimens,  all  some- 
what scoriaceous.  One  of  these  is  from  the  summit  at  an 
altitude  of  nearly  ten  thousand  feet,  the  others  from  the 
bottom  floor.  They  are  all  very  highly  chrysolitic,  and  of 
high  specific  gravity  (G.  =  3-10).  The  similarity  of  the 
hand  specimens  is  so  great  that  they  might  almost  have  been 
taken  from  the  same  block.  They  are  dark-colored,  very 
vesicular,  and  highly  porphyritic,  with  both  chrysolite  and 
augite.  The  large  and  well-formed  crystals  of  augite  often 
have  a  narrow  external  zone  of  deeper  color  (violet-brown), 
and  are  distinctly  pleochroic.  They  are  usually  mottled  with 
inclusions  of  glass  or  iron.  The  chrysolite  shows  but  few 
inclusions.  The  ground  mass  is  thickly  sprinkled  with  iron 
grains,  making  it  nearly  opaque ;  small  triclinic  feldspar 
needles  and  a  secondary  augite  in  minute  form  are  seen.  In 
these  specimens  the  feldspar  must  make  up  but  a  very  incon- 
sideral^le  proportion  of  the  whole.  These  recent  chrysolitic 
basalts  in  Haleakala  are  much  more  porphyritic  and  otherwise 
quite  different  from  the  basalts  of  Mount  Loa  and  Kilauea. 

More  different  still  are  several  specimens  of  the  older 
lavas.  One  of  these  came  from  within  the  crater.  It  is  a 
very  fine-grained,  dark  bluish  gray  rock  of  uniform  texture, 
perfectly  fresh,  and  showing  but  few  minute  cavities.  It  is 
a  feldspathic  rock,  presenting  under  the  microscope  a  rather 
confused  aggregation  of  feldspar  and  augite,  the  latter  in 
minute  grains,  the  whole  thickly  sprinkled  with  grains  of 
iron.  Chrysolite  is  occasionally  noted  in  peculiar  elongated 
forms,  generally  forked  at  both  ends,  and  having  a  border  of 
titanic  iron  grains,  as  before  noted  (Fig.  4,  m).     The  most 


350  PETROGRAPHY   OF   THE    HAWAIIAN   ISLANDS. 

marked  peculiarity  is  the  presence  of  minute  scales  of  a  dark 
brown  mineral,  probably  biotite,  which,  however,  is  only 
present  very  sparingly. 

Another  interesting  specimen  (30)  which  was  obtained 
from  the  top  of  Haleakala  is  a  thin,  almost  schistose  rock, 
light  gray  in  color  and  presenting  the  same  sort  of  an  aggre- 
gation of  feldspar  and  augite  under  the  microscope.  Chry- 
solite, however,  is  a  prominent  constituent,  especially  in  the 
hand  specimen.  There  are  also  large  elongated  but  usually 
ill-defined  aggregates  of  magnetite  grains  marking  the  pres- 
ence of  original  large  individuals,  biotite  or  hornblende,  which 
have  been  re-absorbed  into  the  magma.  Occasional  remnants 
of  the  original  mineral  are  noted,  but  in  very  small  amount. 
Another  curious  feature  of  this  rock  is  the  presence  of  a  zone 
of  augite  about  the  grains  of  chrysolite.  One  case  of  this  is 
illustrated  by  Fig.  4,  :^i.  The  chrysolite  crystal,  though  sepa- 
rated into  different  parts,  has  throughout  the  same  optical  ori- 
entation, as  indicated  by  the  shading,  while  that  of  the  augite 
varies  from  grain  to  grain.  The  mantle  of  magnetite  grains 
about  the  upper  end  of  the  chrysolite  seems  to  represent  the  re- 
mains of  the  augite  which  has  disappeared.  This  re-absorption 
of  augite  is  not  commonly  observed ;  but  this  case,  and  still 
more  another  one  where  of  a  single  augite  crystal  alone  a  large 
part  has  disappeared  in  this  way,  place  the  matter  above 
doubt.  This  zonal  arrangement  of  the  augite  about  the  chryso- 
lite has  been  noted  by  other  observers  in  a  number  of  cases. ^ 

The  structure  and  composition  of  both  these  last-mentioned 
rocks  suggest  that  they  should  perhaps  be  classed  among  the 
augite-andesites  rather  than  the  basalts.  To  decide  this  point 
we  have  the  silica  determinations,  for  which  I  am  indebted 
to  Mr.  Henry  L.  Wheeler,  of  the  Sheffield  Scientific  School. 
He  found  in  the  first  (29)  48-42  p.  c.  SiO.,,  and  in  the  other 
50-44  p.  c,  which  conform  to  that  of  normal  basalt. 

1  See  F.  D.  Adams,  American  Naturalist,  1885,  p.  1087;  G.  H.  Williams,  Amer- 
ican Journal  of  Science,  1886,  xxxi.  35. 


PETROGRAPHY   OF   THE   HAWAHAN   ISLANDS.  351 

The  remaining  specimen  from  the  top  of  Haleakala  is  a 
dark  gray,  almost  black  rock,  of  the  finest  grain,  very  com- 
pact and  breaking  with  a  conchoidal  fracture.  It  is  charac- 
terized by  the  large  amount  of  iron  in  minute  grains  very 
thickly  distributed,  so  as  to  make  the  section  nearly  opaque 
unless  extremely  thin.  The  feldspar  microlites  are  the  most 
prominent  constituent,  and  these  show  a  rather  distinct  flu- 
idal  arrangement.  The  two  specimens  from  Paia  on  Maui 
are  much  like  those  from  Haleakala  just  mentioned,  espe- 
cially No.  29,  and  like  it  they  bear  the  same  resemblance  to 
andesite.  A  curious  point  about  them  is  their  readiness  to 
alter,  the  exposed  surfaces  passing  into  a  soft  earthy  mass  of 
a  light  brown  color. 

The  specimens  from  Western  Maui,  collected  by  Rev.  S.  E. 
Bishop,  are  rocks  of  peculiar  and  interesting  character.  Mr. 
Bishop  says  that  they  are  "  crusts  and  soft  interiors  of  the 
same  formation  (apparently  flowing  lava)  found  on  Launiu- 
poko  Hill,  three  miles  south  of  Lahaina.  A  precisely  similar 
formation  occupies  the  front  of  Mount  Ball,  two  and  one  half 
miles  above  Lahaina.  The  crusts  are  often  rolled  under  the 
gray  soft  material.  Many  crusts  of  grotesque  form  lie  about, 
from  which  the  softer  part  has  been  washed  away.  Many 
portions  of  the  gray  soft  mass  are  of  great  thickness.  Much 
building  stone  has  been  hewn  from  it.  It  presents  no  appear- 
ances of  being  the  result  of  any  decay,  being  compact  and  of 
uniform  texture,  except  the  hard  crusts,  many  of  which  are 
crumpled  up  as  if  in  flowing,  like  pahoehoe." 

One  of  the  specimens  (28)  is  a  whitish  gray  compact  rock, 
whose  surface  is  worn  out  into  a  series  of  deep  holes  between 
projecting  ridges  nearly  one  inch  in  height.  The  texture, 
though  appearing  closely  compact  at  first  sight,  is  seen  by 
the  glass  to  be  minutely  porous,  and  the  surface  is  speckled 
with  very  small  rusty  spots.  Under  the  microscope  it  is  seen 
to  consist  almost  exclusively  of  plagioclase,  here  and  there 
porphyritically  developed ;  there  are  also  the  remnants  of  a 


352  PETROGRAPHY   OF   THE   HAWAHAN   ISLANDS. 

bright  green  pleochroic  mineral  present  in  traces  only,  and 
obviously  the  original  mineral  whose  disappearance  has  left 
the  rusty  spots  ;  it  seems  to  be  hornblende.  A  little  biotite 
is  also  present.  Iron  is  scattered  through  the  mass  rather 
sparingly  in  minute  grains  ;  no  augite  was  noted.  Another 
specimen  shows  the  transition  from  the  firm  rock  to  a  soft 
chalky  condition  powdering  under  the  fingers.  The  section  is 
very  like  the  other  just  described,  though  the  feldspar  is  much 
clouded  and  an  occasional  red  crystal  of  chrysolite  is  noted. 

A  third  specimen  (32)  is  a  flake  from  a  large  bowlder 
(8  X  5  X  4  feet)  found  one  mile  southwest  of  the  summit 
of  Mount  Ball.  Mr.  Bishop  remarks  that  in  the  eroded 
cliff  bowlders  occur  cemented  by  mud,  being  ejectamenta 
from  Mount  Ball.  The  specimen  is  finely  schistose,  and  so 
soft  and  friable  as  to  separate  easily  into  thin  silvery  scales, 
and  by  handling  it  is  soon  reduced  to  ^2 

a  fine  powder.  Microscopic  examina- 
tion shows  it  to  be  very  nearly  the 
same  in  material  with  the  others,  but 
having  a  distinctly  fragmental  appear- 
ance. There  is  more  chrysolite  present 
in  small  broken  fragments  of  crystals ; 
there  is  also  a  little  brown  biotite  in 
scales.  The  mass  is  made  up  of  pene- 
tration twins  of  plagioclase,  according  to  the  Carlsbad  law, 
mostly  arranged  parallel  to  tlie  brachypinacoid,  and  hence 
showing  no  other  kind  of  twinning.  The  form  of  one  of 
these  groups  is  shown  in  Fig.  12.  The  cleavage  marks  the 
position  of  the  basal  plane,  and  the  angle  of  the  section 
(about  80°)  shows  that  it  is  bounded  by  the  planes  c  (001) 
and  y  (2OI).  The  extinction  makes  an  angle  of  a  few  degrees 
with  the  basal  edge,  varying  +  or  —  with  a  slight  change 
in  the  direction  of  the  section.  This  optical  character  and 
the  further  fact  that  the  acute  bisectrix  is  nearly  normal  to 
the   brachypinacoid   would  make  the  feldspar  an   oligoclase. 


PETROGRAPHY   OF   THE   HAWAIIAN   ISLANDS.  353 

Occasional  feldspar  individuals  are  cut  more  nearly  parallel 
to  the  basal  plane,  and  have  the  usual  elongated  form,  and 
show  the  twinning  like  the  other  specimen,  but  as  a  rule  they 
all  lie  nearly  parallel  to  the  brachypinacoid.  The  amount  of 
silica  present,  as;  determined  by  Mr.  Wheeler,  is  61'6o  p.  c, 
which  corresponds  to  the  microscopic  determination.  This  re- 
markable feldspathic  andesyte  is  a  totally  diiferent  rock  from 
any  other  which  has  been  as  yet  obtained  from  the  islands, 
and  the  writer  hopes  to  be  in  the  position  later  to  give  ii 
more  minute  account  of  its  occurrence  and  composition. 

Lavas  of  Oahu. 

Of  the  specimens  in  hand  from  the  island  of  Oahu,  six 
(33,  36,  40,  41,  44,  45)  are  from  the  Kaliuwaa  valley,  near 
Punaluu  on  the  north  side  of  the  island  ;  four  (27,  38,  39,  43) 
are  from  the  Waialua  plain  ;  one  (42)  from  a  point  just  north 
of  Kahuku  Bluff  ;  another  (37)  from  a  gulch  beyond  Monolua, 
four  miles  west  of  Honolulu  ;  and,  finally,  there  are  a  num- 
ber of  specimens  of  the  tufa  froui  the  Punchl^owl,  near  Hono- 
lulu. Among  these  specimens,  two  are  forms  of  higlilv 
chrysolitic  basalts ;  these  are  the  specimens  from  Kahuku 
Bluff  and  one  of  those  from  near  Waialua.  In  the  first  of 
these  (42)  the  chrysolite  makes  up  probably  two  thirds  of  the 
mass  of  the  rock  ;  it  is  present  in  distinct  isolated  crystals, 
having  the  characteristic  form,  each  crystal  having  a  rather 
broad,  rusty  border,  though  the  interior  is  for  the  most  part 
clear  and  unchanged.  The  chrysolite  encloses  grains  of  iron, 
but  very  little  glass.  The  ground  mass  is  a  fine-grained  mix- 
ture of  augite  and  plagioclase  with  considerable  iron,  the 
augite  being  the  more  prominent  constituent. 

In  the  specimen  from  Waialua  (43)  the  chrysolite  is  also 
prominent ;  its  specific  gravity  is  3*06.  With  the  chrysolite, 
the  augite  and  feldspar  also  occur  in  large  individuals  besides 
being  present  in  the  base.     The  feldspar  here  contains  dark- 

45 


354  PETROGRAPHY   OF   THE   HAWAIIAN   ISLANDS. 

colored  glassy  inclusions  in  large  numbers,  arranged  parallel 
to  the  vertical  axis.  The  base  is  a  confused  mixture  of  dirty 
brown  augite  and  feldspar,  with  iron  in  considerable  amount. 
The  specimen  (33)  from  a  dike  in  the  upper  part  of  the  Ka- 
liuwaa  Valley  is  a  very  compact,  nearly  black  basalt,  unusual 
in  showing  occasional  grains  of  j)yrite.  The  feldspar  is  fresh, 
but  the  augite  is  more  or  less  altered  and  its  place  taken  by 
a  serpentinous  substance,  while  occasional  cavities  are  filled 
with  a  light-colored  radiating  zeolitic  mineral  showing  feeble 
double  refraction.  Besides  the  usual  magnetic  iron,  which  is 
scattered  through  in  grains  or  octahedral  crystals,  there  are 
also  curious  aggregations  of  iron  ore  in  very  slender  rod-like 
forms,  sometimes  crossing  each  other  at  right  angles,  but 
usually  matted  together  with  a  confusedly  reticulated  struc- 
ture, sometimes  in  spherical  aggregates.  Specific  gravity,  2-90- 
Chrysolite  is  present  very  sparingly  in  the  remaining  rocks, 
the  hand  specimen  showing  only  here  and  there  an  isolated 
grain,  and  sometimes  close  search  is  needed  to  detect  it. 
They  are  all  light  bluish  gray  basalts,  with  specific  gravity 
ranging  from  2*86  to  2-01.  No  very  close  study  has  been 
made  of  these  specimens,  but  with  a  number  of  them  their 
aspect,  their  highly  feldspathic  character,  and  the  microscopic 
structure  made  it  seem  as  if  they  might  more  properly  be- 
long to  the  andesytes ;  a  silica  determination  of  one  of  them 
(36,  G.  =  2-86)  by  Mr.  Wheeler  gave,  however,  only  50-55 
p.  c.  Si02.  Several  of  these  rocks  show  more  or  less  altera- 
tion, and  in  one  of  them  (36)  the  occasional  crystals  of  chrys- 
olite have  entirely  passed  into  serpentine.  For  the  most  part 
they  are  highly  crystalline,  but  one  of  the  group  (45, G-.  =  2*88) 
shows  numerous  patches  of  a  dark  brown  glass  ;  this  specimen 
is  the  most  highly  chrysolitic  of  the  number,  it  being  present 
in  minute  grains  among  the  feldspar  and  augite,  each  grain 
having  its  orientated  fringe  of  titanic  iron.  No  nepheline- 
basalt  was  detected  among  the  specimens  in  hand. 


pan  Cl^irD* 

VOLCANOES   AND  DEEP-SEA   TOPOGRAPHY. 

IT  htis  become  a  question  of  much  interest  as  regards  the 
origin  of  volcanic  phenomena,  whether  the  profound 
oceanic  depths  which  occur  in  the  vicinity  of  Hawaii  and 
near  some  other  volcanic  islands  are  a  result  in  any  way  of 
the  volcanic  action,  —  either  through  the  undermining  which 
the  discharge  of  the  enormous  amount  of  material  needed 
to  make  mountains  over  thirty  thousand  feet  in  height  from 
the  ocean's  bottom,  and  6°  to  8°  in  mean  slope,  must  have 
occasioned  if  it  were  not  prevented  by  a  continued  and  full 
supply  from  beneath,  or  through  the  gravitational  pressure 
which  has  been  appealed  to  as  the  cause  of  the  ascensive 
force. 

But  is  not  this  inquiry  fully  answered  by  the  principle 
sustained  by  Darwin,  that  the  regions  of  volcanic  islands  in 
the  Pacific  are  areas  of  elevation  ?  It  would  be  so  if  Dar- 
win's conclusion  were  right.  In  the  study  of  the  ocean's 
islands  and  in  Darwin's  account  of  them,  the  author  has 
found  no  facts  that  sustain  the  conclusion.  The  facts  serve 
to  prove,  so  far  as  there  is  any  general  rule,  only  that  such 
islands  have  undergone  less  subsidence  than  the  area  of  coral 
islands. 

The  longer  the  continuance  of  volcanic  action  the  larger 
becomes  the  volcanic  mountain  ;  and  this  principle  is  suffi- 
cient to  account  for  the  great  elevation  of  the  mountains  of 
Hawaii.     There  is  reason  for  believing  that  the  fires  along 


358      VOLCANOES  AND  DEEP-SEA  TOPOGKAPHY. 

the  Hawaiian  line  broke  out  all  together  at  some  time  in 
the  long  past,  but  only  Hawaii  has  kept  on  piling  up  lava- 
streams  from  that  remote  time  of  outbreak  until  now,  and 
hence  has  come  the  altitude  of  these  loftiest  volcanic  moun- 
tains of  the  Pacific;  and  this  in  spite,  it  may  be,  of  much 
subsidence. 

The  question  of  subsidence  through  volcanic  action  and 
its  influence  on  oceanic  topography  i.s  the  subject  before  us. 
Its  consideration  involves  a  general  study  of  the  origin  of 
the  ocean's  deep  troughs  ;  and  this  demands,  as  the  first  step, 
a  general  review  of  oceanic  topography,  —  for  according  to 
recent  bathyraetric  investigations,  the  deep  troughs  are  part 
of  the  system  of  topography,  and  its  grander  part.  We  need 
for  this  purpose  an  accurate  map  of  the  depths  and  heights 
through  all  the  great  area.  Such  a  map  will  ultimately  be 
made  through  the  combined  services  of  the  Hydrographic  De- 
partments of  the  civilized  nations.  At  the  present  time  the 
lines  of  soundings  over  the  oceans,  especially  over  the  Pacific 
and  Indian,  are  few,  and  only  some  general  conclusions  are 
attainable.  It  is  to  be  noticed  that  the  sA^stem  of  features  of 
the  oceanic  area  are  involved  in  the  more  general  terrestrial 
system ;  but  since  the  former  comprises  nearly  three  fourths 
of  the  surface  of  the  sphere,  it  is  not  a  subordinate  part  in 
that  system. 

With  reference  to  this  discussion  of  the  subject  the  author 
has  prepared  the  accompanying  bathj-metric  map. 

The   Bathymeteic  Map,  and  the  general   Features  of 
THE    Oceanic   Depression   displayed   by  it. 

The  Map  (Plate  XVI.).  — In  the  preparation  of  the  bathy- 
metric  map  the  recent  charts  of  the  Hydrographic  Depart- 
ments of  the  United   States  and  Great  Britain  were  used,^ 

*  The  author  is  indebted  to  the  Hydrographic  Departments  of  G-reat  Britain  as 
well  as  the  United  States  for  copies  of  these  ciiarts. 


BATHYMETRIC   MAP.  359 

which  contain  all  depths  to  date,  and  the  lists  of  new 
soundings  published  in  German  and  other  geographical  jour- 
nals. In  order  that  the  facts  on  which  the  bathymetric  lines 
are  based  may  be  before  the  reader,  a  large  part  of  the  depths 
are  given,  but  in  an  abbreviated  form,  100  fathoms  being  made 
the  unit  :  25  signifying  2,500  fathoms  or  nearly  (between 
2,460  and  2,550)  ;  2-3,  about  230  fathoms  ;  -4  about  40  fath- 
oms. Only  for  some  deep  points  is  the  depth  given  in  full. 
The  addition  of  a  plus  sign  (+)  signifies  no  bottom  reached 
by  the  sounding.^ 

In  the  plotting  of  oceanic  bathymetric  lines  from  the  few 
lines  of  soundings  that  have  been  made,  the  doubts  which 
constantly  rise  have  to  be  settled  largely  by  a  reference  to 
the  general  features  of  the  ocean,  and  here  wide  differences 
in  judgment  may  exist  in  the  use  of  the  same  facts  ;  but 
through  the  depths  stated  on  the  map,  the  reader  has  the 
means  of  judging  for  himself.  In  the  case  of  an  island  the 
lines  about  it  may  often  have  their  courses  determined  by 
those  of  adjoining  groups  or  by  its  own  trend  ;  but  in  very 
many  cases  new  soundings  are  needed  for  a  satisfactory 
conclusion. 

Some  divergences  on  the  map  from  other  published  bathy- 
metric maps  require  a  word  of  explanation.  The  northern 
half  of  the  North  Pacific  is  made,  on  other  deep-sea  maps, 

1  On  the  map  the  bathymetric  lines  for  1,000,  2,000,  3,000,  and  4,000  fathoms, 
besides  being  distinguished  in  the  usual  way  by  number  of  dots,  have  been  made 
to  differ  in  breadth  of  line,  the  deeper  being  made  quite  heavy  in  order  to  exhibit 
plainly  the  positions  of  the  areas  without  the  use  of  colors.  The  line  for 
100  fathoms  is,  as  usual,  a  simple  dotted  line.  As  the  bathymetric  map  herewith 
published  is  necessarily  small,  and  none  of  the  ordinary  maps  of  the  oceans  give 
either  deep-sea  soundings  or  a  correct  idea  of  the  trends  of  the  oceanic  ranges 
of  islands,  I  state  here  that  the  charts  of  the  United  States  Hydrographic  Depart- 
ment for  the  Atlantic,  Pacific,  Indian,  and  Arctic  oceans,  may  be  purchased  of  dealers 
in  charts  in  the  larger  sea-board  cities.  There  are  several  large  charts  to  each 
ocean.  One  of  the  firms  selling  them  in  New  York  City  is  that  of  T.  S.  &  J.  D. 
Negus,  140  Water  Street.  The  occasional  bulletins  from  the  Hydrographic  Depart- 
ments of  America  and  Great  Britain  and  Petermann's  Mittheilungen  contain  nearly 
all  the  new  data  issued  for  the  perfecting  of  such  a  chart. 


360     VOLCANOES  AND  DEEP-SEA  TOPOGRAPHY. 

part  of  a  great  3,000-fatliom  area  (between  3,000  and  4,000) 
stretching  from  the  long  and  deep  trough  near  Japan  far 
enough  eastward  to  include  the  soundings  of  3,000  fathoms 
and  over  in  mid-ocean  along  the  thirty-fifth  parallel.  It  has 
seemed  more  reasonable,  in  view  of  present  knowledge  from 
soundings,  to  confine  the  deep-sea  area  off  Japan  to  the 
border-region  of  the  ocean,  near  the  Kurile  and  Aleutian 
islands,  and  leave  the  area  in  mid-ocean  to  be  enlarged  as 
more  soundings  shall  be  obtained.  Again  in  the  South  Pa- 
cific, west  of  Patagonia,  the  area  of  relatively  shallow  sound- 
ings (under  2,000  fathoms)  extending  out  from  the  coast  is 
on  other  maps  bent  southward  at  its  outer  western  limit  so 
as  to  include  the  area  of  similar  soundings  on  the  parallels 
of  40°  and  50°,  between  112°  and  122°  W.  The  prevailing 
trends  of  the  ocean  are  opposed  to  such  a  bend,  and  more 
soundings  are  thought  to  be  necessary  before  adopting  it. 

It  may  be  added  here  that  in  the  Antarctic  Atlantic,  about 
the  parallel  of  66^°  S.  and  the  meridian  of  13i°  W.,  a  large 
area  of  3,000  and  4,000  fathoms  has  b6en  located.  It  was 
based  on  a  sounding  in  1842  by  Captain  Ross,  R.  N.,  in 
which  the  lead  ran  out  4,000  fathoms  without  finding  bot- 
tom. The  sounding  was,  therefore,  made  before  the  means 
available  were  '•  sufficient  to  insure  the  accuracy  of  such 
deep  casts." 

The   Feature-lines   of    the   Oceanic  and  Bordering 

Lands. 

The  courses  of  island-ranges  and  coast-lines  have  a  bear- 
ing on  the  question  as  to  the  courses  of  the  deep-sea  troughs, 
and  therefore,  by  way  of  introduction,  they  are  here  briefly 
reviewed.^     The  system  of  trends  in  feature-lines  takes  new 

^  This  subject  of  the  system  in  the  earth's  feature-lines  is  presented  at  lenqth, 
with  a  map,  in  the  author's  "  Expedition  Geological  Report,"  pp.  11-23  and  414-424  ; 
and  also  more  briefly  in  the  "American  Journal  of  Science,"  1846,  2d  series,  ii.  381. 


FEATURE-LINES   OF   THE   OCEANIC   AND   LAND   AREAS.     361 

significance  from  a  bathymetric  map,  for  the  courses  are  no 
longer  mere  trends  of  islands  or  emerged  mountain  peaks, 
they  are  the  trends  of  the  great  mountain  ranges  themselves ; 
and  in  the  Pacific  these  mountain  courses  are  those  of  half  a 
hemisphere.  Some  of  the  deductions  from  such  a  maj)  are 
briefly  as  follows  :  — 

1.  Over  the  Pacific  area  there  are  no  prominent  north- 
and-south,  or  meridional,  courses  in  its  ranges,  and  none  over 
the  Atlantic,  except  the  axial  range  of  relatively  shallow 
water  in  the  South  Atlantic.  And  to  this  statement  it  may 
pertmently  be  added  that  there  are  none  in  the  great  ranges 
of  Asia  and  Europe,  excepting  the  Urals  ;  none  in  North 
America  ;  none  in  South  America,  excepting  a  part  of  those 
on  its  west  side. 

2.  The  ranges  in  the  Pacific  Ocean  have  a  mean  trend 
of  not  far  from  northwest  by  west,  which  is  the  course  very 
nearly  of  the  longer  diameter  of  the  ocean.  One  transverse 
range  crosses  the  middle  South  Pacific,  —  the  New  Zealand,  — 
commencing  to  the  south  in  New  Zealand  and  the  islands 
south  of  it,  with  the  course  N.  35°  E.,  and  continuing 
through  the  Kermadec  Islands  and  the  Tonga  group,  the 
latter  trending  about  N.  22°  E. ;  and  this  is  the  nearest  to 
north  and  south  in  the  ocean,  except  toward  its  western 
border. 

3.  The  oceanic  ranges  are  rarely  straight,  but  instead 
change  gradually  in  trend  through  a  large  curve  or  a  series 
of  curves.  For  example,  the  chain  of  the  central  Pacific  be- 
comes to  the  westward  north-northwest ;  and  the  Aleutian 
range  and  others  off  the  Asiatic  coast  make  a  series  of  con- 
secutive curves.  Curves  are  the  rule  rather  than  the  excep- 
tion. Moreover,  the  intersections  of  crossing  ranges,  curved 
or  not,  are  in  general  nearly  rectangular. 

4.  Approximate  parallelisms  exist  between  the  distant 
ranges  or  feature-lines  ;  as  (1)  between  the  trend  of  the  New 
Zealand  range  and  that  of  the  east  coast  of  North  America ; 

46 


362      VOLCANOES  AND  DEEP-SEA  TOPOGRAPHY. 

and  also  that  of  South  America  (which  is  continued  across 
the  ocean  to  Scandinavia) ;  also  (2)  between  the  trend  of  the 
foot  of  the  New  Zealand  boot  with  the  Louisiade  group-  and 
New  Guinea  farther  west,  and  the  mean  trend  of  the  islands 
of  the  central  Pacific  both  south  and  north  of  the  equator, 
and  also  that  of  the  north  shore  of  South  America.  These 
are  a  few  examples  out  of  many  to  be  observed  on  the  map. 

5.  The  relatively  shallow-water  area  which  stretches 
across  the  North  Atlantic  from  Scandinavia  to  Greenland  — 
the  Scandinavian  plateau,  as  it  may  well  be  called  —  is  con- 
tinued from  these  high  latitude  seas  southwestward,  in  the 
direction  of  the  axis  of  tlie  North  Atlantic  (or  parallel  nearly 
to  the  coast  of  eastern  North  America  and  the  opposite  coast 
of  Africa),  and  becomes  the  "Dolphin  shoal." 

It  may  be  a  correlate  fact  in  the  earth's  system  of  features 
that  a  Patagonian  plateau  stretches  out  from  the  Patagonia 
coast,  or  from  high  southern  latitudes,  in  the  direction  of  the 
longer  axis  of  the  Pacific,  and  embraces  the  Paumotu  and 
other  archipelagoes  beyond."^  This  Patagonia  plateau  also 
extends  in  the  opposite  direction  over  the  Falkland  Islands 
and  far  beyond. 

The  above  review  of  the  earth's  physiognomy,  if  accom- 
panied In^  a  survey  of  the  map,  may  suffice  for  the  main 
purpose  here  in  view  :  to  illustrate  the  general  truths,  —  that 
s^'stem   in    the    feature-lines  is  a    fact  ;  that   the   system  is 

1  As  parallelisms  may  have  importance  that  is  not  ii<>\v  apparent,  I  draw  atten- 
tion to  one  between  the  Mediterranean  Sea  that  divides  Europe  from  Africa,  and 
the  West  India  (or  West  Mediterranean)  Sea  that  divides  North  from  South 
America.  Both  have  an  eastern,  middle,  and  ivestern  deejj  basin.  Their  depths 
(see  map)  in  the  East  Mediterranean,  are  2,170,  2,040  and  1,585  fathoms  ;  in  the 
West  Mediterranean  (the  three  being  the  Caribbean,  the  West  Caribbean  or 
Cuban,  and  the  Gulf  of  Mexico),  2,804,  3,428,  and  2,080  fathoms.  Further,  in  each 
Mediterranean  Sea,  a  shallow-water  plateau  extends  from  a  prominent  point 
on  the  south  side,  northward,  to  islands  between  the  eastern  and  middle  of  the 
deep  basins,  —  one  from  the  northeast  angle  of  Tunis  to  Sicily,  the  other  from 
the  northeast  angle  of  Honduras  to  Jamaica  and  Hayti,  the  two  about  the  same 
in  range  of  depth  of  water.  And  this  last  parallelism  has  its  parallels  through 
geological  history,  even  to  the  Quaternary,  when  the  great  mammals  made  mi- 
grations to  the  islands  in  each  from  the  continent  to  the  south. 


ORIGIN   OP   THE   DEEP-SEA  TROUGHS.  363 

world-wide  in  its  scope ;  and  —  since  these  feature-lines 
have  been  successively  developed  with  the  progress  of  geo- 
logical history  —  that  the  system  had  its  foundation  in  the 
beginning  of  the  earth's  genesis  and  was  developed  to  full 
completion  with  its  growth. 

Facts   beaeing   on   the    Origin    of   the   Deep-sea 

Troughs. 

In  treating  this  subject,  the  facts  from  tlie  vicinity  of 
volcanic  lands  that  favor  a  volcanic  origin  are  first  men- 
tioned ;  secondly,  those  from  similar  regions  that  are  not 
favorable  to  such  an  origin  ;  thirdly,  facts  from  other  re- 
gions bearing  on  the  question. 

A.   Facts  apparently  favoring  a  Volcanic  Origin. 

1.  The  Pacific  soundings  have  made  known  the  existence 
of  two  deep-sea  depressions,  if  not  a  continuous  trough,  loitli- 
in  forty  miles  of  the  Hawaiian  Islands,  —  one  situated  to  the 
northeast  of  Oahu,  or  north  of  Molokai,  with  a  depth  of 
3,023  fathoms,  or  18,069  feet ;  and  the  other  east  of  the  east 
point  of  Hawaii,  2,875  fathoms,  or  within  750  feet  of  18,000 
feet.  Again,  450  miles  northeast  of  Oahu,  there  is  a  trough 
in  the  ocean's  bottom,  over  800  miles  long,  which  runs  nearly 
parallel  with  the  group  and  has  a  depth  of  3,000  to  3,540 
fathoms  ;  and,  as  far  south,  another  similar  trough  of  prob- 
ably greater  length  has  afforded  soundings  of  3,000  to  3,100 
fathoms.  The  depths  about  the  more  western  part  of  the 
Hawaiian  chain  of  islands  have  not  yet  been  ascertained, 
and  hence  the  limits  of  the  deep  areas  are  not  known.  Such 
depths,  so  close  to  a  line  of  great  volcanic  mountains,  the 
loftiest  of  the  mountains  not  yet  extinct,  appear  as  if  the}' 
might  have  resulted  from  a  subsidence  conseqnent  on  the 
volcanic  action. 

The  subsidence   might  have  taken  place  (1)  either  from 


364      VOLCANOES  AND  DEEP-SEA  TOPOGRAPHY. 

underminings,  which  the  amount  of  matter  thrown  out 
and  now  constituting  the  mountain  chain,  with  its  peaks  of 
20,000  to  30,000  feet  above  the  sea-bottom,  shows  may  be 
large  ;  or  (2)  from  the  gravitational  pressure  in  the  earth's 
crust  about  a  volcanic  region  which  speculation  makes  a 
source  of  the  ascensive  force  and  of  the  upward  rising  of 
the  lavas, — the  subsiding  crust  following  down  the  liquid 
surface  beneath.  In  either  case  the  mass  of  ejected  material 
might  be  a  measure  more  or  less  perfect  of  the  maximum 
amount  of  subsidence. 

2.  In  the  western  part  of  the  North  Pacific,  at  the  south 
end  of  the  volcanic  group  of  the  Ladrones,  off  the  largest 
island  of  the  group,  Guam,  the  ''Challenger"  found  a  depth 
of  4,475  fathoms,  one  of  the  two  deepest  spots  yet  known 
in  the  Pacific.  The  situation  with  reference  to  the  group 
is  like  that  off  the  east  end  of   the    Hawaiian  group. 

3.  In  the  South  Pacific,  not  far  southwest  of  Tongatabu, 
the  largest  island  of  the  Tonga  or  Friendly  group,  depths 
of  4,295  and  4,428  fathoms  were  obtained  in  soundings  by 
Capt.  Pelham  Aldrich,  of  H.  M.  S.  "  Egeria,"  in  latitudes 
24°  49',  24°  37'  S.,  and  longitudes  175°  07',  175°  08'  W.  In 
latitude  24°  00'  and  longitude  175^  16'  the  depth  found  was 
3,692  fathoms;  in  24°  27'  and  176°  15',  530  fathoms;  in  23° 
12',  175°  40',  596  fathoms.^ 

4.  East  of  Japan  and  the  Kuriles,  a  region  of  ranges  of 
volcanoes,  there  is  the  longest  and  deepest  trough  of  the 
ocean,  first  made  known  by  the  soundings  of  the  United 
States  ship  "  Tuscarora ; "  the  length  is  1,800  miles,  the 
depths  4,000  to  4,650  fathoms  ;  and  farther  northeast,  south 
of  one  of  the  Aleutian  Islands,  a  depth  of  4,037  fathoms  oc- 
curs again,  also  obtained  by  the  "Tuscarora;"  and  depths  of 
3,100  to  3,664  fathoms  exist  still  farther  east.  It  is  prob- 
able that  the  4,000-line  trough  continues  from  the  Kuriles 

*•  American  Journal  of  Science,  1889,  xxxvii.  420,  and  Bulletin  of  the  British 
Hydrographic  Department  of  February,  1889. 


ORIGIN   OF  THE   DEEP-SEA  TROUGHS.  365 

to  this  deep  spot  off  the  Aleutian  volcanic  range  ;  and  if 
so,  the  length  of  the  trough  is  over  2,500  miles.  The  map 
is  made  to  suggest  its  extension  still  farther  eastward  ;  but 
among  the  few  soundings  made  off  the  more  eastern  Aleu- 
tians, the  deepest  are  3,664  and  3,820  fathoms,  near  longi- 
tude 165°  W.  The  latter  was  obtained  hy  the  "Albatross," 
of  the  United  States  Fish  Commission,  in  1888,  in  latitude  52° 
20'  N.  and  165°  W.  Farther  west  the  '■  Albatross  "  found,  in 
latitude  52°  18' N.  and  longitude  163°  54'  W.,  a  depth  of 
2,848  fathoms;  in  52°  20'  N.,  166°  05MY.,  2,654  fathoms; 
in  52°  40'  N.,  166°  35'  W.,  2,267  fathoms.  —  indicating,  as  the 
report  states,  that  the  depression  of  3.000  to  3,820  fathoms 
is  not  continued  w^estward. 

Other  similar  facts  may  be  found  on  the  map ;  and  still 
others  may  exist  which  are  not  now  manifest,  owing  to  the 
sinking  of  oceanic  areas  and  islands.  But  no  cases  can  be 
pointed  out  which  are  more  decisively  in  favor  of  volcanic 
origin. 

B,    Facts  from  the  A'icinity  op  VolcaxNic  Regions  apparently 

NOT   REFERABLE    TO    A    YOLCANIC    ORIGIN. 

The  ocean  off  the  western  border  of  North  and  South 
America  affords  striking  examples  of  the  absence  of  deep 
troughs  from  the  vicinity  of  regions  eminently  volcanic.  The 
South  American  volcanoes  are  many  and  lofty ;  and  still  the 
ocean  adjoining  is  mostly  between  2,000  and  2,700  fathoms 
in  depth ;  and  just  south  of  Valparaiso,  it  shallows  to  1,325 
fathoms.  The  only  exception  yet  observed  is  that  of  a  short 
trough  of  3,000  to  3,368  fathoms,  close  by  the  Peruvian 
shore.  It  may,  however,  prove  to  be  a  long  trough,  al- 
though certainly  stopping  short  of  Valparaiso.  The  waters, 
however,  of  the  Pacific  border  of  both  South  and  North 
America  deepen  abruptly  compared  with  those  of  the  At- 
lantic border ;  and  the  significance  of  this  fact  deserves 
consideration. 


366      VOLCANOES  AND  DEEP-SEA  TOPOGRAPHY. 

The  facts  off  Central  America  are  more  remarkable  than 
those  off  the  coast  to  the  south.  The  volcanoes  are  quite 
near  to  the  Pacific  coast,  and  still  the  depths  are  between 
1,500  and   2,500  fathoms. 

The  condition  is  the  same  off  the  west  coast  of  North 
America.  Of  the  two  areas  of  3,000  or  more  fathoms 
nearest  to  the  east  coast  of  the  North  Pacific,  one  is  600 
miles  distant  in  tlie  latitude  of  San  Francisco,  and  the 
other  is  w^ithin  ten  degrees  of  the  equator  and  twenty 
degrees  of  the  coast ;  both  are  too  far  away  to  be  a  con- 
sequence of  volcanic  action  in  California,  Mexico,  or  Central 
America. 

In  the  North  Atlantic  the  European  side  lias  its  volcanoes, 
and  has  had  them  since  the  Silurian  era,  and  yet  the  non- 
volcanic  North  American  side  of  the  ocean  has  far  the  larger 
areas  of  deep  water  and  much  greater  mean  depth.  The 
Azores  or  Western  Islands,  which  are  all  volcanic,  have 
depths  around  them  of  only  1,000  to  2,000  fathoms  and  no 
local  troughs.  Iceland,  the  laud  of  Hecla,  is  in  still  shal- 
lower waters,  with  no  evidence  of  local  depressions  off  its 
shores.  Tlie  Canaries  are  volcanic,  Imt  no  deep  trough  is 
near  them. 

c.   Facts  from  Regions  not  Volcanic  which  are  unfavorable 
TO  THE  Idea  of  a  Volcanic  Origin. 

1.  In  tlie  North  Pacific,  near  its  centre,  the  area  of  3,000 
or  more  fathoms  about  35°  N. ;  the  two  similar  but  smaller 
areas  toward  its  eastern  border ;  the  areas  north  of  the 
Carolines,  in  the  western  part  of  the  ocean  ;  the  broad  equa- 
torial area  about  the  Phoenix  Group  ;  the  area  in  the  South 
Pacific  in  170°  W.,  east  of  Chatham  Island,  and  another  just 
south  of  Australia,  —  are  all  so  situated  tha.t  no  reason  is 
apparent  for  referring  them  to  a  volcanic  origin.  Some  of 
the  areas  are  in  the  coral-island  latitudes,  and  the  supposed 
volcanic  basis  of  coral  islands  makes  a  volcanic  origin  pos- 


ORIGIN   OF   THE   DEEP-SEA   TROUGHS.  367 

sible ;  but  their  probable  size  and  position  appear  to  favor 
the  idea  of  origin  through  some  more  fundamental  cause. 
The  area  in  the  South  Pacific,  east  of  Chatham  Island,  is 
450  miles  distant  from  the  land.  The  border  of  southern 
Australia,  abreast  of  the  deep-sea  trough,  has  no  known 
volcano. 

2.  1)1  tlte  Atlantic  away  from  the  West  Indies.  —  The  3,000- 
fathom  areas  of  the  North  and  South  Atlantic  —  that  is,  the 
three  in  the  North  Atlantic,  the  two  in  the  South  Atlantic, 
and  the  two  equatorial,  one  near  the  coast  of  Guinea  and  the 
other  near  that  of  South  America  —  occupy  positions  that  sug- 
gest no  relation  to  volcanic  conditions.  The  Cape  Verdes, 
north  of  the  equator,  are  partly  encircled  by  one  of  the  deep 
areas,  somewhat  like  the  eastern  end  of  the  Hawaiian  group ; 
but  this  bathymetric  area  appears  to  be  too  large  to  owe 
its  origin  directly  to  volcanic  work  in  the  group.  The  coast 
of  Guinea  near  the  3,000-fathom  area  has  nothing  volcanic 
about  it,  and  the  opposite  coast  of  South  America,  near  an- 
other, is  free  from  volcanoes. 

The  only  facts  in  the  Atlantic  that  suggest  a  volcanic 
origin  are  the  depression  of  2,445  fathoms  within  forty 
miles  of  the  west  side  of  the  volcanic  Cape  Verde  Archi- 
pelago, and  that  of  2,060  fathoms  within  twenty  miles  of 
Ascension  Island  ;  and  a  connection  is  possible. 

3.  In  and  near  tlte  West  Indies.  —  The  most  remarkable  of 
the  depths  of  the  Atlantic  area  are  situated  in  and  near  the 
region  of  the  West  Indies,  as  is  well  illustrated  and  discussed 
by  Mr.  Alexander  Agassiz  in  his  instructive  work  on  the 
''  Three  Cruises  of  the  Blake."  The  deepest  trough  of  the 
ocean  (4,561  fathoms)  occurs  within  seventy  miles  of  Porto 
Rico  ;  and  yet  this  island  has  no  great  volcanic  mountain, 
though  having  basaltic  rocks.  By  the  north  side  of  the 
Bahama  belt  of  coral  reefs  and  islands,  for  400  miles,  as 
Mr.  Agassiz  well  illustrates,  the  depth  becomes  2,600  to 
3,000  fathoms  within  twenty  miles  of  the  coast-line,  and  at 


368  VOLCANOES   AND  DEEP-SEA   TOPOGRAPHY. 

one  point  2,774  within  eight  miles,  a  pitch-down  of  1:2-5; 
and  nothing  suggests  a  volcanic  cause  for  the  abrupt  descent. 
Cuba  and  Hayti  are  not  volcanic,  and  look  as  if  they  were  an 
extension  of  Florida,  so  that  no  grounds  exist  for  assuming 
that  the  Bahamas  rest  on  volcanic  summits. 

One  of  the  strangest  of  3,000-fathom  troughs  is  that  which 
commences  off  the  south  shore  of  eastern  Cuba,  having  there 
a  depth  of  3,000  to  3,180  fathoms.  It  is  within  twenty 
miles  of  this  non-volcanic  shore,  and  nearly  three  times  this 
distance  from  Jamaica.  No  sufficient  reason  appears  at  pres- 
ent for  pronouncing  its  origin  volcanic.  It  is  continued  in  a 
west-by-south  direction  to  a  point  beyond  the  meridian  of  85° 
W.,  or  over  700  miles,  making  it  a  very  long  trough,  and  the 
depths  vary  from  2,700  to  3,428  fathoms.  The  depression 
extends  on  into  the  Gulf  of  Honduras,  carrying  a  depth  of 
2,000  fathoms  far  toward  its  head,  and  in  a  small  indenta- 
tion of  the  coast  it,  stops  ;  for  nothing  of  it  appears  in  the 
outline  of  the  Pacific  coast  or  the  depths  off  it,  and  nothing 
in  the  range  of  volcanic  mountains  on  the  coast.  Against 
the  three  deepest  parts  of  the  trough  there  are  (1)  the 
Grand  Cayman  reef,  twenty  miles  north  of  a  spot  3,428 
fathoms  deep ;  (2)  banks  in  13  and  15  fathoms  within 
fifteen  miles  of  a  depth  of  2,982  fathoms  ;  and  (3)  Swan 
Island  reef,  fifteen  miles  south  of  a  depth  of  3,010  fathoms  ; 
the  first  of  the  three  indicating  a  slope  to  the  bottom  of  1 :  5, 
and  the  last  of  1 :  4-4.  Why  these  greatest  depths  in  the 
trough,  so  abrupt  in  depression,  should  be  on  one  side  of 
shoals  or  emerged  coral  reefs,  it  is  not  easy  to  explain  ; 
and  the  less  so  that  the  part  of  the  trough  south  of  Cuba 
has  nothing  volcanic  near  by  in  the  adjoining  mountain 
range,  and  the  fact  also  that  the  westernmost  end  of  the 
trough  extends  on  for  175  miles,  and  there  has  a  depth  of 
3,048  fathoms  with  2,000  fathoms  either  side  and  no  coral 
reefs. 


ORIGIN   OF   THE   DEEP-SEA   TROUGHS.  369 

D.    ArRANGEIMENT  OP"  THE  DeEP-SEA  TROUGHS  IN  THE  HaLVES   OF  THE 

Oceans  pointing  to  some  other  than  a  Volcanic  Origin. 

The  ivcstern  half  of  the  Atlantic  and  Pacific  oceans  con- 
tains much  the  larger  part  of  the  3,000-fathom  areas  and 
all  the  depths  over  4,000  fathoms.  In  the  North  Atlantic 
the  areas  of  3,000  and  over  in  the  western  half,  or  off  the 
coast  of  the  United  States,  are  very  large ;  and  the  bathy- 
metric  line  of  2,500  fathoms  extends  westward  nearly  to 
the  1,000-fathom  line.  This  important  feature  can  be  ap- 
preciated for  both  oceans  from  a  look  at  the  map,  without 
special  explanations. 

As  a  partial  consequence  of  this  arrangement,  the  Pacific, 
viewed  as  a  whole,  may  be  said  to  have  a  westward  sloj)e  in 
its  bottom,  or  from  the  South  American  coast  toward  Japan. 
This  westward  slope  of  the  bottom  exists  even  in  the  area 
between  New  Zealand  and  Australia,  —  the  ocean  in  this  area 
being  shallow  for  a  long  distance  from  the  coast  on  the  east 
side  and  deepening  to  2,500  -  2,700  fathoms  close  to  that 
non-volcanic  land,  New  South  Wales  or  eastern  Australia. 
In  the  Atlantic  the  slope  is  in  the  direction  of  its  northeast- 
southwest  axis,  either  side  of  the  Dolphin  shoal,  but  espe- 
cially the  western  side,  rather  than  from  east  to  west,  it 
commencing  in  the  Scandinavian  plateau  and  ending  in  tlie 
great  depths  adjoining  the  West  Indies. 

Owing  to  the  system  in  the  Atlantic  topography,  the  Dol- 
phin Shoal  —  the  site  of  the  Atlantis  of  ancient  and  modern 
fable  —  is  really  an  appendage  to  the  Eastern  Continent  (that 
is,  to  Europe),  and  is  shut  off  by  wide  abyssal  seas  from  the 
lands  to  the  west  that  have  been  supposed  to  need  its  gravel 
for  rock-makins;. 

But  the  view  that  the  west  half  of  an  oceanic  basin  is 
always  the  deepest  becomes  checked  by  finding  in  the  In- 
dian Ocean  that  the  only  areas  that  are  3,000  fathoms  deep 
or  over  are  in  the  eastern  part  of  the  ocean,  off  the  north- 

47 


370  VOLCANOES   AND   DEEP-SEA   TOPOGRAPHY. 

west  coast  of  Australia,  and  near  western  Java  and  Sumatra. 
The  greatest  depths  in  its  western  half,  or  toward  Africa,  are 
2,400  to  2,600  fathoms.i 

Conclusions. 

1.  The  facts  reviewed  lead  far  away  from  the  idea  that 
volcanic  action  has  been  jDi^edominant  in  determining  the  po- 
sition of  the  deep-sea  troughs.  It  has  probably  occasioned 
some  deep  depressions  within  a  score  or  two  of  miles  of  the 
centre  of  activity,  ]:)ut  beyond  this  the  great  depths  have 
probably  had  some  other  origin. 

2.  It  is  further  evident  that  the  deep-sea  troughs  are  not  a 
result  of  superficial  causes  of  trough-making.  Erosion  over 
the  ocean's  bottom  cannot  excavate  isolated  troughs.  The 
coldest  water  of  the  ocean  stands  in  the  deep  holes  or  troughs 
instead  of  running,  as  the  reader  of  Agassiz's  volume  has 
learned. 

The  superficial  operation  of  weighting  the  earth's  crust 
with  sediment,  or  with  coral  or  other  organic-made  limestone, 
and  filling  the  depressions  as  fast  as  made,  much  appealed  to 
in  explanations  of  subsidence,  has  not  produced  the  troughs ; 
for  filled  depressions  are  not  the  kind  under  consideration. 
Moreover,  the  areas  are  out  of  the  reach  of  continental  sedi- 
ments, and  too  large  and  deep  to  come  within  the  range  of 
possibilities  of  organic  sedimentation  or  accumulation.  The 
existence  of  the  troughs  is  sufficient  proof  of  this.  The  deep 
troughs  of  the  West  Indian  and  adjoining  seas  are  in  a  region 
of  abundant  pelagic  and   sea-border  life,  and  j^et  the  marvel- 

^  In  the  Arctic  seas,  going  north  from  the  Scandinavian  platean,  the  vrater 
deepens  north  of  the  hititude  of  IceUxnd,  l)et\veen  Greenland  and  Spitzbergen,  to 
2,000  fathoms,  and  farther  north  to  2,650  fathoms,  in  the  longitude  nearly  of  Green- 
wich ;  and  it  is  probable  that  the  2000-fathom  area  extends  over  the  region  of  the 
North  Pole.  The  continents  of  Europe  (with  Asia  probably)  and  North  America 
are  proved,  by  the  shallow  soundings  over  the  adjoining  Arctic  seas  and  the  islands 
or  emerged  land,  to  extend  to  about  82|-''  N.,  which  is  about  450  miles  from  the 
pole. 


ORIGIN  OF  DEEP-SEA  TOPOGRAPHY.  371 

lous  depths  exist.  And  the  depths  of  the  open  oceans  are 
no  less  without  explanation.  Those  close  by  the  Bahamas, 
extending  down  to  sixteen  and  eighteen  thousand  feet,  are 
evidence  of  great  subsidence  from  some  cause ;  and  the  coral 
reefs  for  some  reason  have  manifestly  kept  themselves  at  the 
surface  in  spite  of  it. 

o.  If  superficially  acting  causes  are  insufficient,  we  are  led 
to  look  deeper,  to  the  sources  of  the  earth's  energies,  or  its  in- 
terior agencies  of  development,  to  which  the  comprehensive 
system  in  its  structure  and  physiognomy  points.  Whatever 
there  is  of  system  in  the  greater  feature-lines,  whether  marked 
in  troughs  or  in  mountain  chains  or  island  ranges,  must  come 
primarily  from  systematic  work  within.  The  work  may  have 
been  manifested  in  long  lines  of  flexures  or  fractures  as 
steps  in  the  process,  but  the  conditions  which  gave  directions 
to  the  lines  left  them  subject  to  local  causes  of  variation,  and 
between  the  two  agencies  the  resulting  physiognomy  has 
been  evolved. 

We  have  from  the  Pacific  area  one  observation  of  a  vol- 
canic nature  bearing  on  the  comprehensiveness  of  the  system 
of  feature-lines  in  the  oceans ;  and  although  I  have  already 
referred  to  it,  I  here  reproduce  the  facts  for  use  in  this  place. 

If  the  ranges  of  volcanic  islands  were,  in  their  origin,  lines 
of  fissures  as  a  result  of  comprehensive  movements,  the  lines 
should  continue  to  be  the  courses  of  planes  of  weakness  in 
the  earth's  crust.  The  New  Zealand  line,  including  the  Ker- 
madec  Islands  and  the  Tongan  group,  has  been  pointed  to 
as  one  of  these  lines,  and  one  of  great  prominence,  since  it  is 
the  chief  northeastward  range  of  the  broad  Pacific,  and  nearly 
axial  to  the  ocean.  The  series  of  volcanoes  along  the  axis 
of  New  Zealand  is  in  the  same  line.  It  was  noticed,  at  the 
Tarawera  eruption  of  1883,  that  four  or  Jive  days  after  the 
outbreak,  and  three  after  it  had  subsided,  White  Island,  in 
the  Bay  of  Plenty,  at  the  north  end  of  the  New  Zealand 
series,  became  unusually  active ;  and  two  months  later  there 


372      VOLCANOES  AND  DEEP-SEA  TOPOGRAPHY. 

was  a  violent  eruption  in  the  Tonga  group,  on  the  Island  of 
Niuafou.  The  close  relation  in  time  of  the  latter  to  the 
New  Zealand  eruption  is  referred  to  by  Mr.  C.  Trotter,  in 
"  Nature  "  of  Dec.  7,  1886.'  May  it  not  be  that  these  dis- 
turbances were  due  to  a  slight  shifting  or  movement  along 
a  series  of  old  planes  of  fractures,  successively  from  south  to 
north,  and  hence  that  even  now  changes  of  level  may  take 
place  through  the  same  comprehensive  cause  that  determined 
the  existence  of  the  earth's  feature-lines?  Owing  to  the  long 
distance  of  the  Tonga  group  from  New  Zealand,  an  affirma- 
tive reply  to  the  question  cannot  be  positively  made  ;  but 
there  is  probability  enough  to  give  great  interest  to  this 
branch  of  geological  inquiry. 

*  American  Journal  of  Science,  1887,  xxxiii.  311. 


DENUDATION   OF  VOLCANIC   ISLANDS ;    ITS   AMOUNT 
A   MARK   OF   AGE. 

SINCE  the  evidence  from  denudation  of  the  lapse  of  time 
is,  as  already  shown,  a  subject  of  much  geological  in- 
terest, and  one  discussed  at  length  in  the  author's  "  Expedi- 
tion Geological  Report,"  some  facts  and  conclusions  are  here 
cited  from  it,  especially  those  with  regard  to  the  island  of 
Tahiti,  of  the  Society  Group,  and  the  Hawaiian  Islands. 

The  island  of  Tahiti  has  nearly  the  shape,  as  regards  out- 
line, of  the  figure  8,  and  was  once  a  twin  of  volcanoes.  Only 
the  northern  and  larger  of  the  two  peninsulas  is  often  visited, 
and  to  that  the  following  remarks  refer.  It  was  originally  a 
gently  sloping  cone  of  the  type  represented  by  the  Hawaiian 
volcanoes  ;  for  its  beds  of  lavas,  as  seen  in  the  sides  of  the 
valleys,  slope  at  a  small  angle  toward  the  shores ;  mostly 
3°  to  10"  —  varying  in  some  parts  to  15°  —  on  the  north  and 
west  sides,  where  the  author's  examinations  were  made. 
Supposing  the  mean  slope  to  be  8°,  the  height  above  the 
sea-level  of  the  original  cone  —  the  diameter  of  the  island 
being  twenty  miles  —  would  have  been  nearly  seventy-five 
hundred  feet.  It  probably  much  exceeded  this ;  for  the 
greatest  height  at  the  present  time,  according  to  an  imper- 
fect measurement  made  by  Lieut.  W.  M.  Walker,  U.  S.  N., 
of  the  Wilkes  Exploring  Expedition  (who  took  as  a  base 
a  line  measured  on  the  coral  reef  near  Matavai),  is  about 
seven  thousand  feet. 


374  DENUDATION   OF   VOLCANIC   ISLANDS. 

The  old  cone  is  now  a  dissected  mountain  ;  the  dissector 
was  running  water.  Valleys  cut  profoundly  into  its  sides 
and  lay  bare  the  centre  to  a  depth  of  from  two  thousand 
to  nearly  four  thousand  feet  (by  estimate)  below  the  exist- 
ing summit ;  and  the  deep  valleys  crowd  on  one  another, 
owins;  to  the  extent  of  the  erosion. 

The  topographic  features  of  the  island  are  shown  on  the 
accompanying  map.  This  map  is  a  copy  m  the  main  of  that 
in  Captain  Wilkes's  ''Narrative"  of  the  Expedition;  —  in 
the  main,  because  changes  have  been  made  by  the  author, 
removing  some  of  the  imperfections  introduced  by  the  art 
of  the  map-maker  or  engraver  and  his  want  of  knowledge  of 
the  region.  This  liberty  would  not  have  been  taken,  were 
it  not  that  part  of  the  map  was  originally  from  a  sketch  by 
the  author,  communicated  to  the  Hydrographic  Department 
of  the  Expedition.  This  sketch  comprised  the  northern  third 
of  the  island,  from  the  centre  outward,  between  the  Papenoo 
and  Punaavia  valleys,  and  was  prepared  from  personal  ol)- 
servations  in  the  valleys  of  the  region,  obtained  on  an  ascent 
of  Mount  Aorai,  one  of  the  two  highest  peaks,  but  without  a 
proper  survey  beyond  a  few  bearings.  Being  the  only  person 
of  the  Expedition  who  made  the  ascent,  no  other  one  had  the 
opportunity  for  so  comprehensive  a  view  of  the  ridges  and 
valleys  of  that  part  of  the  island.  Of  the  central  peaks,  the 
highest,  at  a  on  the  map,  made  seven  thousand  feet  in  height 
by  Lieutenant  Walker's  measurement,  is  called  Orohena  ;  the 
next  highest,  about  five  hundred  feet  lower,  at  6,  is  the  one 
called  Aorai. 

The  island  in  its  present  condition,  as  the  map  shows,  is 
an  admirable  model  of  a  deeply  denuded  or  water-sculptured 
mountain-cone.  To  appreciate  the  precise  conditions  under 
which  the  denudation  went  forward,  it  has  to  be  borne  in 
mind  that  the  waters  from  the  rains  and  clouds  are  most 
abundant    about   the    summits   and   higher   portion    of   the 


DENUDATION   OF   VOLCANIC   ISLANDS. 


375 


island,  and  are  there  perpetually  at  work.  In  these  upper 
parts,  therefore,  or  above  fifteen  hundred  feet,  forests  and 
shrubbery  cover  the  ridges  and  valleys  wherever  there  is  a 
foothold  :   but    toward   the  coast,   or  below  a  level  of   one 


Map  of  Tahiti,  tlie  corul-reefs  excluded;  the  lower  side  is  the  northern,  or  that 
toward  the  equator :  PP,  village  of  Papenoij ;  M,  of  Matavai ;  P,  of  Papaua ;  T,  of 
Toanoa ;  P',  of  Papieti,  the  largest ;  P",  of  Punaavia.  The  valleys  are  named  from 
the  villages  on  the  coast  at  their  termination. 

thousand  to  fifteen  hundred  feet,  the  slopes,  down  to  the 
grove-clad  border-plain  of  the  island,  are  grass-covered  and 
look  bare  in   the  distant  view. 

The  following  are  the  features  due  to  the  erosion :  — 
1.    The  ridges  and  valleys  are  arranged  nearly  radially. 


376 


DENUDATION   OF   VOLCANIC   ISLANDS. 


2.  The  highest  peaks  are  about  the  centre. 

3.  The  valleys  terminate  for  the  most  part  near  the  sea- 
level  instead  of  extending  deeply  beneath  it,  as  is  proved  by 
the  fact  that  the  outline  of  the  island  is  nearly  even,  instead 
of  being  indented  with  deep  bays. 

4.  The  larger  of  these  valleys  abut  at  their  heads 
against  the  central  peaks  in  lofty  precipices,  —  precipices  of 
two  to  nearly  four  thousand  feet.  Some  of  the  larger  val- 
leys are  widest  at  the  centre  of  the  island  and  terminate 
under  the  peaks  in  vast  amphitheatres. 

5.  The  ridges  toward  the  borders  of  the  island  are 
somewhat  broad-backed,  but  over  the  interior  very  narrow. 
Above  an  elevation  of  three  thousand  feet  or  so  (as  I  found 
in  my  ascent),  the  top  edge  of  tlie  ridges  for  much  of  the 
way  is  but  three  or  four  feet  wide,  —  too  thin  to  be  repre- 
sented on  a  map  of  so  small  a  scale  as  the  above  ;  and  in 
some  spots  it  diminishes  to  a  foot,  and  even,  at  times,  to 
a  thin  edge  of  bare  rock  ;  and  from  the  crest  the  declivities 
either  side  pitch  off  steeply  one  to  two  thousand  feet. 

6.  Within  a  mile  or  two  of  ihe  central  peaks  erosion  has 
reduced  the  height  of  some  of  the  narrow  ridges  a  thousand 
feet  or  more,  or  still  further  lowered  and  thinned  them  until 
dwindled  to  a  mere  pinnacled  wall  at  the  base  of  the  peaks. 
A  view  of  a  portion  of 
one  of  these  thinned- 
down  ridges  (called, 
on  the  island,  the 
Crown)  is  here  intro- 
duced. The  ascent  of 
one  of  the  highest 
peaks  is  possible  only 
along  a  ridge  that  has 
kept  unbroken  its  con- 
nection with  the  summit,  and  an  experienced  guide  is  needed 
to  make  sure  of  the  right  and  safe  way. 


M^^m^fi  ill 


ii-/-a 


The  "  Crown  "  at  the  head  of  the  Papiete 
Valley. 


DENUDATION   OF   VOLCANIC   ISLANDS.  377 

Some  incidents  connected  with  the  author's  ascent  of  Aorai 
will  make  the  facts  better  appreciated  :  ^  — 

"  We  commenced  the  ascent  by  the  ridge  on  the  west  side 
of  the  Matavai  Valley,  and,  by  the  skilfulness  of  our  guide, 
were  generally  able  to  keep  the  elevated  parts  of  the  ridge 
without  descending  into  the  deep  valleys  which  bordered 
our  path.  An  occasional  descent  and  a  climb  on  the  op- 
posite side  of  the  valley  were  undertaken ;  and  although  the 
sides  were  nearly  perpendicular,  it  was  accomplished  with- 
out much  difficulty,  by  clinging  from  tree  to  tree,  with  the 
assistance  of  ropes,  at  times,  where  the  mural  front  was 
otherwise  impassable.  By  noon  of  the  second  day  we  had 
reached  an  elevation  of  five  thousand  feet,  and  stood  on  an 
area  twelve  feet  square,  the  summit  of  an  isolated  crest  in 
the  ridge  on  which  we  were  travelling.  To  the  east  we 
looked  down  two  thousand  feet  into  the  Matavai  vallev  ; 
to  the  west  a  thousand  feet  into  a  branch  of  the  Papaua 
valley,  the  slopes  either  way  being  from  sixty  to  eighty 
degrees,  or  within  thirty  degrees  of  perpendicular.      On  the 

^  On  the  excursion  I  had  with  me  only  two  Tahitians.  The  ascent  was  made 
after  Captain  Wilkes  had  left  Tahiti  with  his  vessel,  the  "  Vincennes,"  and  hence 
the  mistaken  statement  in  his  "  Narrative  "  that  I  was  accompanied  by  others  of  the 
expedition. 

Very  few  of  the  natives  then  living  had  ever  been  to  the  summit  of  this  moun- 
tain, and  great  difficulty  was  found  in  obtaining  a  guide  acquainted  with  the  route. 
Paths  led  as  lar  as  the  Feiis,  or  mountain  plantains,  an  elevation  of  one  thousand 
to  fifteen  hundreil  feet  ;  but  beyond  this  the  tops  of  the  ridges  are  mostly  covered 
with  a  wiry  brake  (Gleichenium),  which  grows  in  some  places  to  a  height  of  ten 
feet,  and  is  almost  impenetrable.  In  order  to  pass  through  it,  we  had  to  break  it 
down  by  throwing  our  bodies  at  full  length  upon  it  or  by  diving  into  it  ;  or,  where 
too  high  to  admit  of  this  mode  of  progress,  we  had  recourse  to  burrowing,  pushing 
aside  and  breaking  oft"  its  crowded  stems,  and  thus  we  dug  our  way  for  rods.  In 
addition  to  the  brake,  the  shrubbery  often  formed  a  dense  thicket,  impassable  ex- 
cept with  a  hatchet.  These  obstacles  made  progress  slow  ;  and  without  a  native  tc 
lead  the  wa}^  the  jaunt,  difficult  in  itself,  would  have  been  quite  impracticable  in 
the  five  days  allotted  to  it.  Another  discomfort  on  the  route  was  the  want  of 
water,  which,  after  a  few  days  of  dry  weather,  is  seldom  to  be  found  in  the  valleys 
near  the  summit.  A  traveller  in  the  mountains  of  Tahiti  should  go  well  provided 
against  this  inconvenience.  We  found  dew  from  the  leaves  a  great  luxury  ;  and 
the  news  that  water  had  been  found  in  a  valley  created  a  sensation  of  pleasure 
scarcely  describable. 

48 


378 


DENUDATION   OF   VOLCANIC   ISLANDS. 


side  of  our  ascent,  and  beyond,  on  the  opposite  side,  our 
peak  was  united  with  the  adjoining  summit  by  a  thin  ridge, 
reached  by  a  steep  descent  of  three  hundred  feet.  This  ridge 
was  described,  by  our  natives,  as  no  wider  at  top  than  a 
man's  arm ;  and  a  fog  coming  on,  they  refused  to  attempt  it 
that  day.  The  next  morning  being  clear,  we  pursued  our 
course.  For  a  hundred  rods  the  ridge  on  which  we  walked 
was  two  to  four  feet  wide,  and  from  it  we  looked  down  on 
either  side  a  thousand  feet  or  more  of  almost  perpendicular 
descent.  Beyond  this  the  ridge  continued  narrow,  though 
less  dangerous,  until  we  approached  the  high  peak  of  Aorai. 
This  peak  had  appeared  to  be  conical  and  equally  accessible 
on  different  sides;  but  it  proved  to  have  but  one  place  of 
approach,  and  that  along  a  wall  with  precipices  of  two  to 
three  thousand  feet,  and  seldom  exceeding  two  feet  in  width 
at  top.  In  one  place  we  sat  on  it  as  on  the  back  of  a  horse,  — 
for  it  was  no  wider.  —  and  pushed  ourselves  along  till  we 
reached  a  spot  where  its  width  was  doubled  to  two  feet, 
and,  numerous  bushes  again  affording  us  some  security,  we 
dared  to  walk  erect.     We  at  last  stood  perched  on  the  sum- 


Peaks  of  Orohena,  with  Pitoiiiti  to  thk  left. 
(As  seen  from  the  summit  of  Aorai.) 

mit  edge,  not  six  feet  broad.  The  ridge  continued  beyond 
for  a  short  distance,  with  the  same  sharp,  knife-edge  char- 
acter, and  was  then  broken  off  by  the  Punaavia  valley. 
Our  height  afforded  a   near  view  of  Orohena ;  it  was  sepa- 


DENUDATION   OF   VOLCANIC    ISLANDS.  379 

rated  from  us  only  by  the  valley  of  Matavai,  from  whose 
profound  depths  it  rose  with  nearly  erect  sides.  The  peak 
is  saddle-shaped,  and  the  northern  of  the  two  points  is  called 
Pitohiti/  These  summits,  and  the  ridge  which  stretches 
from  them  toward  Matavai,  intercepted  the  view  to  the 
southward.  In  other  directions  the  rapid  succession  of  gorge 
and  ridge  that  characterizes  Tahitian  scenery  was  open  be- 
fore us.  At  the  western  foot  of  Aorai  appeared  the  Crown. 
Beyond  it  extended  the  Punaavia  valley,  the  only  level  spot 
in  sight ;  and  far  away,  in  the  same  direction,  steep  ridges, 
rising  behind  one  another  with  jagged  outline,  stood  against 
the  western  horizon.  To  the  north,  deep  valleys  gorge  the 
country,  with  narrow  precipitous  ridges  between  ;  and  these 
melt  away  into  ridgy  hills  and  valleys,  and  finally  into  the 
palm-covered  plains  bordering  the  sea. 

"  On  the  descent  we  followed  the  western  side  of  the 
Papaua  valley,  along  a  narrow  ridge,  such  as  has  been  de- 
scribed, only  two  or  three  feet  wide  at  top,  with  precipices 
either  side  of  not  less  than  a  thousand  feet.  Proceeding 
thus  for  two  hours,  using  the  bushes  as  a  kind  of  balustrade 
though  occasionally  startled  by  a  slip  of  the  foot  one  side  or 
the  other,  our  path  suddenly  narrowed  to  a  mere  edge  of 
naked  rock,  and,  moreover,  the  ridge  was  inclined  a  little  to 
the  east,  like  a  tottering  wall.  Taking  the  upper  side  of  the 
sloping  wall,  and  trusting  our  feet  to  the  bushes  while  cling- 
ing to  the  rocks  above,  carefully  dividing  our  weight  lest  we 
should  precipitate  the  rocks  and  ourselves  to  the  depths  below, 
we  continued  on  till  we  came  to  an  abrupt  break  in  the  ridge 
of  twenty  feet,  half  of  which  was  perpendicular.  By  means  of 
ropes  doubled  around  the  rocks  above,  we  in  turn  let  ourselves 
down,  and  soon  reached  again  a  width  of  three  feet,  where 
we  could  walk  in  safety.  Two  hours  more  at  last  brought 
us  to  slopes  and  ridges  where  we  could  breathe  freely." 

^  The  sketch  on  page  378  is  from  the  author's  note-book  of  1839  ;  it  was  not 
used  in  his  Report. 


380  DENUDATION   OF  VOLCANIC   ISLANDS. 

The  peculiarities  here  described  characterize  all  parts  of 
the  island.  Toward  the  high  peaks  of  the  interior  the 
ridges  which  radiate  from  or  connect  with  them  become 
mere  mountain  walls  with  inaccessible  slopes,  and  the  val- 
leys are  from  one  to  three  thousand  feet  in  depth.  The 
central  peaks  themselves  have  the  same  wall-like  character. 
It  is  thus  with  Orohena  and  Pitohiti,  as  well  as  Aorai ; 
and  owing  to  the  sharpness  of  the  summit  edge,  rather 
than  the  steepness  of  the  ascent,  Orohena  is  said  to  be  quite 
inaccessible. 

Now  contrast  this  dissected  volcanic  mountain  v/ith  those 
of  the  Hawaiian  Islands  :  ^  — 

"Mount  Loa,  whose  sides  are  still  flooded  with  lavas  at 
intervals,  has  but  one  or  two  streamlets  over  all  its  slopes, 
and  the  surface  has  none  of  the  deep  valleys  common  about 
other  summits.  Volcanic  outflows  have  kept  its  surface 
essentially  even,  and  by  its  continuation  to  this  time,  the 
waters  have  had  scarcely  a  chance  to  make  a  beginning 
in  denudation.  Mount  Kea,  which  has  been  extinct  for  a 
long  period,  has  a  succession  of  valleys  on  its  windward  or 
rainy  side  which  are  several  hundred  feet  deep  at  the  coast 
and  gradually  diminish  upward,  extending  in  general  about 
one  half  or  two  thirds  of  the  way  to  the  summit.  But  to 
westward  it  has  dry  declivities,  which  are  comparatively  even 
at  the  base,  with  little  running  water.  A  direct  connection  is 
thus  evinced  between  a  windward  exposure  and  the  existence 
of  valleys.  And  we  observe  also  that  the  time  since  volcanic 
action  ceased  is  approximately  or  relatively  indicated  ;  for  it 
has  been  long  enough  for  the  valleys  to  have  advanced  only 
part-way  to  the  summit.  Degradation  from  running  water 
would  of  course  commence  on  such  slopes,  —  that  is,  the  wind- 
ward slopes,  —  at  the  foot  of  the  mountain,  where  the  waters 
are  necessarily  more  abundant  and  more  powerful  in  denud- 

1  Pages  379-392:  "  On  the  Origin  ot  the  Valleys  and  Ridges  of  the  Pacific 
Islands." 


DENUDATION   OF  VOLCANIC   ISLANDS.  381 

ing  action,  in  consequence  of  tlieir  gradual  accumulation  on 
their  descent. 

'^  Haleakala,  or  eastern  Maui,  offers  the  same  facts  as 
Mount  Kea,  indicating  the  same  relation  between  the  features 
of  the  surface  and  the  climate  of  the  different  sides  of  the 
island.  On  eastern  Oaliu  the  valleys  are  much  more  exten- 
sive ;  yet  still  the  slopes  of  the  original  cone  may  be  in  part 
distinguished.  And  thus  we  are  gradually  led  to  Kauai, 
where  the  valleys  are  very  profound  and  the  former  slopes 
can  hardly  be  made  out.  The  facts  are  so  progressive  in 
character  that  all  must  be  equally  attributed  to  the  running 
water  of  the  land.  The  valleys  of  ]Mount  Kea,  extending 
some  thousands  of  feet  up  its  sides,  sustain  us  in  saying  that 
time  only  is  required  for  explaining  the  existence  of  any 
similar  valleys  in  the  Pacific.  " 

The  Report  adds  the  following  in  explanation  :  — 
"Suppose  a  mountain  sloping  around  like  a  volcanic  dome 
of  the  Pacific.  The  excavating  power  at  work  proceeds  from 
the  rains  or  condensed  vapor,  and  depends  upon  the  amount 
of  water  and  rapidity  of  slope.  The  transporting  force  of 
flowing  water  as  shown  by  Hopkins  increases  as  the  sixth 
power  of  the  velocity,  —  double  the  velocity  giving  sixty-four 
times  the  trtinsporting  power.  Hence,  if  the  slopes  are  steep, 
the  water  gathering  into  rills  excavates  so  rapidly  that  every 
growing  streamlet  ploughs  out  a  gorge  or  furrow ;  and  con- 
sequently the  number  of  separate  gorges  is  very  large,  and 
their  sizes  comparatively  small,  though  of  great  depth,  —  a 
condition  well  illustrated  on  northeastern  Maui.  The  exca- 
vation above,  for  a  while,  is  feeble  in  amount;  the  waters 
accumulate  as  they  descend,  causing,  especially  during  the 
rainy  seasons,  the  denudation  to  be  greatest  below,  and  in  this 
part  the  gorge  or  valley  most  rapidly  forms.  In  its  progress 
it  enlarges  from  below  upward,  though  also  increasing  above, 
while  at  the  same  time  the  many  tributaries  are  making 
lateral    branches.      Toward  the  foot    of    the    mountain    the 


382  DENUDATION   OF   VOLCANIC   ISLANDS. 

excavating  power  gradually  ceases  when  the  stream  has  no 
longer  m  this  part  a  rapid  descent,  —  that  is,  whenever  the 
slope  is  not  above  a  few  feet  to  the  mile.  The  stream  then 
consists  of  two  parts,  the  torrent  of  the  mountains  and  the 
slower  waters  below,  and  the  latter  is  gradually  lengthening 
at  the  expense  of  the  former. 

"  After  the  lower  waters  have  nearly  ceased  excavation,  a 
new  process  connnences  in  this  part,  —  that  of  widening  the 
valley.  The  stream,  which  here  effects  little  change  at  low 
water,  is  flooded  in  certain  seasons,  and  the  abundant  waters 
act  laterally  against  the  inclosing  rocks.  Gradually,  through 
this  undermining  and  denuding  operation,  the  narrow  bed  be- 
comes a  flat  strip  of  land  between  lofty  precipices,  through 
which,  in  the  rainy  seasons,  the  streamlet  flows  in  a  winding 
course.  The  streamlet,  after  the  flat  bottom  of  the  valley  is 
made,  deposits  detritus  on  its  banks,  which  in  some  places  so 
accumulates  as  to  prevent  an  overflow  of  the  banks  by  any 
ordinary  freshet.  Such  is  the  origin  of  the  deep  channels 
with  a  riband  of  land  at  bottom  that  cut  through  the  di- 
viding plain  of  Oahu,  and  which  are  common  toward  the 
shores  of  many  of  the  Pacific  islands. 

"  The  torrent  part  of  the  stream,  as  it  goes  on  excavating 
is  gradually  becoming  more  and  more  steep.  The  rock- 
material  operated  upon  consists  of  layers  of  unequal  hard- 
ness, varying  but  little  from  horizontality  while  dipping  to- 
ward the  sea,  and  this  occasions  the  formation  of  cascades. 
AVhenever  a  softer  layer  wears  more  rapidly  than  one  above, 
it  causes  an  abrupt  fall  in  the  stream  :  it  may  be  at  first  but 
a  few  feet  in  height ;  but  the  process  begun,  it  goes  on  with 
accumulating  power.  The  descending  waters  in  this  spot  add 
their  whole  weight,  as  well  as  a  greatly  increased  velocity,  to 
their  ordinary  force  ;  and  the  excavation-  below  goes  on  rap- 
idly, removing  even  the  harder  layers.  The  consequences  are, 
a  fall  of  increasing;  heio-ht,  and  a  basin-like  excavation  di- 
rectly  beneath   the  fall.     Often,  for  a  short  distance  below. 


DENUDATION   OF   VOLCANIC   ISLANDS.  383 

the  stream,  moves  quietly  before  ru.shing  again  on  its  torrent 
course  ;  and  when  this  result  is  attained  by  the  action,  the 
height  of  the*  fall  has  nearly  reached  its  limit  so  far  as  exca- 
vation below  is  concerned,  though  it  may  continue  to  increase 
from  the  gradual  wear  and  removal  of  the  rocks  over  which 
it  descends. 

"  As  the  gorge  increases  in  steepness,  the  excavations  above 
deepen  rapidlj^  —  the  more  rapid  descent  more  than  compen- 
sating, it  may  be,  for  any  difference  in  the  amount  of  water. 
Moreover,  as  the  rains  are  generally  most  frequent  at  the 
very  summits,  the  rills  in  this  part  are  kept  in  almost 
constant  action  through  the  year,  while  a  few  miles  nearer 
the  sea  they  are  often  dried  up  or  absorbed  among  the  cav- 
ernous rocks.  The  denudation  is  consequently  at  all  times 
great  about  the  higher  parts  of  the  valley,  especially  after 
the  slopes  have  become  steep  by  previous  degradation,  and 
finally  an  abrupt  precipice  forms  its  head. 

"  The  waters  descending  the  ridges  either  side  of  the  valley, 
or  gorge,  are  also  removing  these  barriers  between  adjacent 
valleys,  and  are  producing,  as  a  first  effect,  a  thinning  of  the 
ridge  at  summit  to  a  mere  edge  ;  and  as  a  second,  its  partial 
or  entire  removal,  so  that  the  two  valleys  may  at  last  be 
separated  only  by  a  low  wall,  or  even  terminate  in  a  common 
head,  —  a  ivide  amjy/iitheatre  enclosed  hy  the  lofty  r}%ountams. 
In  one  case  the  ridge  between  the  two  valleys,  which  toward 
the  shores  of  the  island  has  rather  a  broad  back,  high  up 
in  the  region  of  mists  and  frequent  rains  becomes  a  narrow 
wall,  and  thus  connects  with  the  central  summit.  In  the 
other,  the  ridge  finally  terminates  abruptly,  and  a  deep 
valley  separates  it  from  the  main  mountain. 

'•'  We  have  here  to  remember  that  these  mountain  streams 
at  times  increase  their  violence  a  million-fold  when  the  rains 
swell  the  waters  to  a  flood.  There  is  everything  favorable 
for  degradation  which  can  exist  in  a  land  of  perpetual  sum- 
mer :  and  there  is  a  full  balance  ag-ainst  the  frosts  of  colder 


384  DENUDATION   OF   VOLCANIC   ISLANDS. 

regions  in  the  exuberance  of  vegetable  life,  since  it  occasions 
rapid  decomposition  of  the  surface,  covering  even  the  face  of 
a  precipice  with  a  thick  layer  of  altered  rock,  and  with  spots 
of  soil  wherever  there  is  a  chink  or  shelf  for  its  lodgment. 
The  traveller  ascending  a  valley  on  one  of  these  islands  on  a 
summer  day,  when  the  streams  are  reduced  to  a  mere  rill 
which  half  the  time  burrows  out  of  sight,  seeing  the  rich 
foliage  around,  vines  and  flowers  in  profusion  covering  the 
declivities  and  festooning  the  trees,  and  observing  scarcely  a 
bare  rock  or  stone  excepting  a  few,  it  may  be,  along  the 
bottom  of  the  gorge,  might  naturally  question  with  respect  to 
the  agents  which  had  channelled  the  lofty  mountains  to  their 
base.  But  tliough  silent,  the  agents  are  still  on  every  hand 
at  work  :  decomposition  is  in  slow  but  constant  j)rogress  ; 
and  the  percolating  waters  are  acting  internally  if  not  at 
the  surface.  Moreover,  at  another  season,  he  would  find  the 
scene  changed  to  one  of  noisy  waters  careering  over  rocks 
and  plunging  down  heights  w^ith  frightful  velocity.  Then 
the  power  of  the  stream  would  not  be  disputed." 

The  Report  concludes  with  the  remark :  — 

"  With  literal  truth,  therefore,  we  may  speak  of  the  valleys 
of  the  Pacific  islands  as  the  furrowings  of  time,  and  read  in 
them  marks  of  age.  We  learn  from  such  facts  how  com- 
pletely the  features  of  an  island  may  be  obliterated  by  this 
simple  process ;  that  even  a  cluster  of  peaks  like  Orohena, 
Pitohiti  and  Aorai  of  Tahiti  may  be  derived  from  a  simple 
volcanic  dome  or  cone.  Mount  Loa  contains  within  itself  the 
material  from  which  an  island  like  Tahiti  might  be  modelled 
that  should  have  nearly  twice  its  height  and  four  times  the 
geographical  extent." 

Great  denudation  on  the  leeioayxl  side  of  an  island  is  an 
exception  to  the  usual  rule.  It  is  a  consequence,  on  Oahu,  of 
the  sharp-crested  twenty-mile  precipice  facing  to  the  wind- 
ward}     The    trade-winds    become    chilled   on    striking   the 

1  See  page  282  and  Map  on  Plate  XIII. 


DENUDATION   OF   VOLCANIC   ISLANDS.  885 

summit  of  the  precipice,  and  ready,  therefore,  to  drop  their 
moisture  ;  but  as  they  are  moving  on,  they  get  beyond  the 
summit  before  much  of  the  moisture  falls,  and  so  the  lee- 
ward slopes  receive  the  water.  In  the  upper  part  of  the 
Nuuanu  valley,  within  two  miles  of  the  paU,  one  hundred 
and  thirty-two  inches  of  rain  fall  a  year,  and  nearly  one  hun- 
dred inches  less  than  this  at  Honolulu,  although  brief  sprink- 
lings occur  almost  daily  over  the  city.  Konahuanui  and 
Lanihuli,  in  the  view  from  Honolulu,  are  generally  under 
clouds  ;  but  from  Kaneohe,  they  are  usually  imcovered. 

A  nearly  similar  condition  exists  in  West  Maui,  owing  to 
the  thinness  of  the  rocky  walls  at  the  head  of  its  great  val- 
leys. Very  broad  valleys  are  consequently  made  there  on  the 
leeward  side,  as  in  Oahu,  as  shown  on  Plate  XII. ;  but  these 
valleys  end  below  rather  abruptly  in  a  slender  gulch,  which 
may  be,  for  the  most  of  the  year,  a  "dry  run;"  the  ex- 
cessively dry  and  hot  airs  of  the  lower  plains  carrying  away 
the  water  and  supplying  almost  none. 

This  subject  of  denudation  and  the  making  of  valleys  is  so 
well  illustrated,  also,  by  the  facts  which  the  author  observed 
in  New  South  Wales  in  the  interval  between  his  visit  to 
Tahiti  in  1839  and  to  the  Hawaiian  Islands  in  1840,  that  a 
few  additional  pages  are  here  cited  from  his  Report.^ 

"  The  great  depth,  extent,  and  number  of  the  vallej^s  of 
New  South  Wales  are  calculated  to  excite  wonder  and  per- 
plex us  much  in  the  study  of  their  origin.  In  some  of  these 
sandstone  regions  the  gorges  intersect  the  country  in  endless 
succession,  and  are  alike  in  their  inaccessible  precipices  of 
one,  two,  or  three  thousand  feet.  They  are  deep  gulfs,  with 
walled  sides,  composed  of  horizontal  layers  of  sandstone. 
These  layers  seem  once  to  have  been  continuous  ;  and  what 
is  the  force  which  has  thus  channelled  the  mountain  struc- 

^  Pages  526-532 :  on  "  Degradation  of  the  Rocks  of  New  South  Wales  and 
Formation  of  the  Valleys." 

49 


386  DENUDATION   OF   VOLCANIC   ISLANDS. 

ture  ?  Are  they  ^  stupendous  rents  in  the  bosom  of  the 
earth  ? '  ^  Are  they  regions  of  subsidence  ?  Can  it  be  that 
they  were  ijever  filled,  but  were  depressions  left  between  the 
heaps  of  accumulating  sediment  that  constitute  the  sand- 
stone, which  depressions  were  afterwards  enlarged  by  the  sea 
during  the  elevations  of  the  land  ?^  Or  may  we  adopt  the 
'  preposterous  '  idea  that  simple  running  water  has  been  the 
agent ;  and  if  so,  was  it  fresh  water  or  that  of  the  ocean  ? 

"  The  forms  of  these  valleys  are  as  remarkable  as  their  ex- 
tent. Major  Mitchell  states  that  Cox  River  rises  in  the  vale 
of  Clywd,  2,150  feet  above  the  sea,  and  leaves  this  expanded 
basin  through  a  gorge  2,200  yards  wide,  flanked  on  each  side 
by  rocks  of  horizontally  stratified  sandstone  800  feet  high : 
here  it  joins  the  Warragamba.  Some  of  its  tributaries  rise 
at  a  height  of  3,500  feet  above  the  sea,  and  the  ravines  they 
occupy  cover  an  area  of  1,212  miles.  From  this  he  calculates 
that  one  hundred  and  thirty-four  cuhic  miles  of  stone  have 
been  removed  from  the  valley  of  the  Cox.^ 

"  The  facts  observed  by  us  are  sufficient  to  substantiate  the 
general  conclusion  of  Major  Mitchell.  The  Kangaroo  valley 
is  another  example  of  a  valley  two  to  three  miles  in  width, 
and  a  thousand  to  eighteen  hundred  feet  deep,  opening  out- 
ward through  a  comparatively  narrow  gap  ;  and  by  a  rough 
calculation  from  our  own  examinations  and  the  map  of  Ma- 
jor Mitchell,  the  amount  of  rock  necessary  to  fill  the  valley 
is  equivalent  to  a  rectangular  ridge  twelve  miles  long,  two 
miles  wide,  and  two  thousand  feet  deep.  This  is  but  a  small 
example,  however,  compared  with  those  of  the  interior.  Mr. 
Darwin  remarks  upon  this  peculiarity  of  form,  —  their  extent 
and  width  and  many  branches,  yet  narrow  openings  at  their 
lower  extremity  ;  and  he  observes  that  the  same  is  the  char- 
acter of  the  bays  along  the  coast. 

1  Count  Strzelecki,  in  his  "  New  South  Wales  and  Van  Diemen's  Land,"  p.  57. 
-  Darwin,  in  his  "  Volcanic  Islands,"  p.  137. 
8  Mitchell's  Expedition  into  Australia,  ii.  352. 


DENUDATION    OF   VOLCANIC   ISLANDS.  387 

"  The  ideca  that  runnmg  water  was  the  agent  in  these  openi- 
tions  appears  not  so  '  preposterous  '  to  us  as  it  was  deemed 
by  Mr.  Darwin,  and  we  think  that  Major  Mitchell  was  right 
in  attributing  the  effects  to  this  cause.  The  extent  of  the 
results  is  certainly  no  difficulty  with  one  who  admits  time 
to  be  an  element  which  a  geologist  has  indefinitely  at 
command.  We  need  but  refer  to  the  facts  from  the  Pacific 
islands  to  show  that  New  Holland,  after  all,  is  not  the  most 
remarkable  land  in  the  world  for  valleys  of  denudation. 

"We  should  consider  that  the  rock  material  is  far  more 
yielding  than  that  of  basaltic  Tahiti.  Indeed  the  whole 
rock,  from  the  uppermost  layer  to  the  deposits  below  the 
coal,  is  remarkably  fragile,  considering  the  age  of  the  de- 
posits, crumbling  readily,  and  often  breaking  without  diffi- 
culty between  the  fingers  ;  and  besides  it  is  much  fissured. 
Even  the  harder  fossiliferous  Wollongong  rock,  as  has  been 
described,  falls  to  pieces  of  itself  when  exposed  to  the  air. 
Moreover,  there  are  occasionally  clayey  or  argillaceous  lay- 
ers which  are  still  softer  ;  and  many  of  those  of  the  coal 
formation  are  not  firmer  than  the  material  of  a  common 
clay-bank.  The  denudation  of  such  material  requires  no 
preparatory  decomposition,  as  with  many  igneous  rocks,  but 
takes  place  from  wear  alone,  and  wiih  but  slight  force  in 
the  agent. 

"  It  is  obvious,  for  the  same  reason,  that  the  material  car- 
ried off  by  denudation  ought  not  to  appear  in  fragments 
through  the  lower  country.  A  short  journey  along  a  rapid 
stream  would  reduce  even  large  masses  to  powder.  The 
plains  of  the  Kangaroo  valley  are  covered  in  places  with 
basaltic  pebbles  or  bowlders  ;  but  the  sandstone,  which  is  the 
prevailing  rock  along  the  bed  of  the  stream  and  in  the  en- 
closing hills,  has  scarcely  a  representative  pebble  in  the  de- 
bris. The  sandstone  blocks  are  worn  to  sand  and  earth  by 
the  torrents,  while  the  harder  basalt  is  slowly  rounded.  On 
the  plains  of  Puenbuen   similar  facts  were  apparent.     The 


388  DENUDATION   OF   VOLCANIC   ISLANDS. 

hills  contain  sandstone  and  basalt,  but  only  the  latter  ap- 
pears as  bowlders  or  pebbles  over  the  plains,  or  along  the 
streams  below. 

"  This  Sydney  sandstone  does  not  even  require  running 
water  to  promote  degradation.  In  many  caverns  along 
cliffs,  the  rock  gradually  falls  to  pow^der  by  a  species  of 
efflorescence.  There  are  numerous  instances  of  this  along 
the  coves  of  Port  Jackson,  where  the  crystallization  of  the 
saline  spray  reduces  the  rock  to  its  original  sand  ;  and  in 
the  interior  of  the  country  there  are  large  caves,  formed 
apparently  by  this  same  process,  though  probably  from  the 
.crystallization  of  nitrates.  Near  Puenbuen,  these  caves  are 
from  six  to  twenty  feet  deejD,  and  from  four  to  forty  long. 
The  roof  is  arched,  and  appears  to  be  constantly  crumbling, 
while  the  bottom  is  covered  with  a  fine,  dry,  ash-like  sand, 
into  which  the  feet  sink  several  inches.  The  same  operation 
is  going  on  along  the  summits  of  the  Illawarra  range ;  and 
one  huge  block  was  found  so  hollowed  out  in  this  way  as 
to  be  a  mere  shell,  which  sounded  under  the  hammer  like 
a  metallic  vessel. 

"  These  various  facts  bring;  before  us  some  idea  of  the 
yielding  nature  of  the  rock  which  the  waters  have  to  con- 
tend with  in  the  denudation  of  this  country,  and  they  also 
illustrate  the  various  processes  at  w^ork.  We  allude  to  a 
single  other  mode  of  degradation  before  passing  :  it  is  the 
action  of  growing  trees  and  their  roots,  both  in  opening 
fissures  and  tumbling  blocks  down  the  precipices.  It  is 
a  cause  influencing  very  decidedly  the  characters  of  cliffs, 
and  at  the  same  time  preparing  the  rock  for  decomposition 
and  wear. 

"  The  credibility  of  the  view  here  favored  is  further  sus- 
tained by  the  character  of  the  streams.  The  great  ex- 
tent of  the  floods  and  the  rapid  rise  of  the  rivers  attending 
them  have  been  alluded  to.  The  stream  of  the  Kangaroo 
Grounds,  when   visited   by  the  writer,   was  a   mere  brook, 


DENUDATION   OF   VOLCANIC   ISLANDS.  389 

fordable  in  any  part ;  and  it  flowed  along  with  quiet  miir- 
murinirs.  But  a  few  weeks  before  the  brook  was  a  river 
thirt}'  feet  deep,  driving  on  in  a  broad  torrent,  and  flooding 
the  valley.  If,  as  has  been  shown,  the  transporting  power 
of  running  water  increases  as  the  sixth  power  of  the  velo- 
city, and  a  stream  of  fifteen  miles  an  hour  has  more  than 
ten  times  the  transporting  power  of  one  moving  ten  miles 
an  hour,  and  more  than  a  million  times  that  of  a  stream  of 
two  miles  an  hour,  we  can  comprehend  how  inadequate  must 
be  the  conceptions  of  this  force  which  we  derive  from  view- 
ing the  streams  at  low  water. 

"  This  rise  in  the  Kangaroo  Grounds  is  an  index  of  what 
takes  place  every  few  years  over  the  whole  countr3^  Sur- 
prise at  the  amount  of  degradation  subsides  before  such 
facts  ;  we  rather  wonder  that  sandstones  so  soft  and  fragile, 
which  have  been  exposed  probably  from  the  Oolitic  period, 
still  cover  the  surface  to  so  great  an  extent  as  they  do  at 
the  present  time. 

"  Mr.  Darwin  derived  his  principal  argument  against  the 
hypothesis  of  denudation  from  the  forms  of  the  valleys, — 
their  width,  extent,  and  ramifications,  and  yet  narroiu  em- 
bouchures. But  we  find  on  consideration  that  this  form  is 
a  necessary  result  of  the  mode  of  denudation  under  the  cir- 
cumstances existing.  In  the  account  of  the  valleys  of  the 
Pacific  islands  it  has  been  shown  that  the  gorges  change 
their  character  where  the  slopes  become  quite  gradual,  from 
a  narrow  defile  with  convergent  sides  to  a  broad  channel 
with  vertical  walls  and  flat  bottom.  The  same  cause  should 
produce  a  like  effect  in  Australia.  A  stream,  in  making  a 
descent  of  two  or  three  thousand  feet  from  the  higher  sum- 
mits to  the  level  of  the  sea,  gradually  deepens  its  bed  by 
wear.  Since  the  waters  are  increasing  in  quantity  from 
various  sources  as  they  flow  onward,  this  deepening  of  the 
gorge  should  be  most  rapid  at  its  lower  extremity  ;  and  it 
would   continue   in  progress  until  the  bed   in    that  part   be- 


390  DENUDATION   OF   VOLCANIC   ISLANDS. 

came  so  low  or  gradual  in  slope,  that  the  waters  had  lost  to 
a  large  degree  their  eroding  force,  and  any  excavation  at 
bottom  was  made  up  by  the  material  deposited  along  its 
course.  This  fact  determines  a  permanent  height  for  the 
bottom  of  the  lower  valley.  As  the  stream  continues  its 
wearing  action  in  the  same  manner,  the  lower  valley  is 
gradually  prolonged  upward,  retaining  nearly  the  same  slope 
at  bottom  (one  or  two  feet  to  the  mile) ;  consequently  the 
steeper  portion  of  the  gorge  is  at  the  same  rate  becoming 
shorter  and  still  steeper.  Thus  the  head  of  the  stream  may 
finally  become  a  series  of  cascades,  or,  as  happens  at  times 
in  the  Pacific,  it  may  be  reduced  mostly  to  a  single  cascade 
of  a  thousand  feet  or  more. 

"  The  progress  of  this  change  may  be  better  understood 
from  the  f  olio  win  o;  diao:ram  :  — 


Ai 


— B 


A  B  C  D  is  the  rock  to  be  cut  through  by  the  stream. 
Suppose  denudation  to  produce  first  the  course  C  n^.  The 
stream  is  filled,  as  is  commonly  the  case,  by  lateral  channels 
and  rills  down  the  sides  of  the  gorge,  as  well  as  by  the  main 
source  ;  and  the  amount  or  depth  of  water  is  thus  in  con- 
stant increase,  as  it  flows  onward.  Denudation  is  conse- 
quently most  rapid  the  farthest  from  the  head,  or  toward 
n^ ;  the  valley,  tlierefore,  increases  in  depth  in  this  part  till 
the  slope  has  l^ecome  so  gentle  here  as  to  counterbalance  the 
greater  amount  of  water,  at  which  point  the  bottom  of  the 
valley  ceases  to  increase  in  depth  ;  in  this  condition  v^  n^  be- 
comes the  bottom  of  the  lower  valley,  and  C  n^  the  steeper 
portion  above  it.  In  the  same  manner  the  valley  bottom 
continues  to  prolong  at  nearly  the  same  slope,  and  C  u^, 
C  n*,    C  71^  become    successively    the    course    of    the  stream 


DENUDATION   OF   VOLCANIC    ISLANDS.  391 

descending  into  it.     And  even  C  if'  is  not  an  exaggeration  of 
possibilities,  for  many  examples  of  it  are  met  with. 

''  But  the  results  explained  are  but  a  part  of  the  actua-l 
course  of  things  in  these  regions  of  horizontally  stratified 
rock.  As  on  Oahu  and  elsewhere,  when  the  denudation 
at  bottom  has  reached  its  limit,  the  waters  exert  but  little 
degrading  power  except  during  floods,  and  this  takes  place 
by  the  sides  of  the  overflowing  stream;  at  the  same  time 
depositions  of  detritus  take  place  along  its  banks.  The 
result  is  that  the  rocks  bounding  the  valley  are  worn  away 
below,  and  are  often  undermined ;  the  valley  widens  at 
bottom  to  a  flat  plain,  while  the  enclosing  wall  by  the  pro- 
cess becomes  nearly  vertical.  A  narrow  riband  of  land  be- 
tween high  precipices  of  rock  is  therefore  a  necessary  result 
of  the  action. 

"  Degradation  still  continues  along  the  upper  or  steep  part 
of  the  main  stream,  and  also  along  the  many  streamlets  and 
rills  pouring  down  the  valley's  sides  ;  and  in  each  of  these 
streamlets  there  is  a  tendency  to  produce  below  a  flat-bot- 
tomed valley.  The  consequence  is  that  they  increase  the 
width  and  extent  of  the  main  valley-plain  ;  for  whenever 
they  become  thus  flat-bottomed,  they  contribute  to  its  lateral 
enlargement. 

"  At  the  same  time  the  bluffs  at  the  lower  extremity,  or  em- 
bouchure, of  the  main  valley  remain  without  much  change, 
since  the  denudation  is  mostly  confined  to  the  vicinity  of 
the  streamlets  alluded  to,  and  these  streamlets  are  most  abun- 
dant above,  they  being  produced  and  fed  mainly  by  the  rains 
in  the  higher  parts  of  the  mountains.  It  is  natural  enough, 
therefore,  that  the  valleys  should  not  only  become  flat  below 
and  precipitous  in  their  sides,  but  also  that  they  should  widen 
least  at  their  lower  extremity.  We  see,  consequently,  no 
necessity  of  appealing  to  any  other  cause  than  that  of  run- 
ning water  to  account  for  the  most  stupendous  results  in 
Australia. 


392  DENUDATION   OF  VOLCANIC   ISLANDS. 

'•  It  has  been  supposed  that  the  sea  has  been  largely  con- 
cerned in  the  denudation  which  has  produced  the  Australian 
valleys.  We  find  no  reason  for  attributing  any  of  the  val- 
leys to  this  source,  although  it  is  possible  that  some  modifi- 
cations may  thus  have  resulted.  The  facts  at  Port  Jackson 
are  a  sufficient  reply  on  this  point.  The  cliffs  of  the  estuary 
actually  undergo  very  little  change  from  the  action  of  its 
waters,  and  are  far  more  altered  by  the  mode  of  efflorescence 
described  and  by  rills  of  running  water ;  and  such  action  as 
is  exerted  tends  to  remove  headlands  instead  of  deepening 
the  coves. 

"  The  proper  action  of  the  sea  is  seen  in  the  character  of 
the  sandstone  shores  of  East  Australia,  and  especially  in  the 
wide  platform  of  rock  below  high-tide  level  lying  at  the  foot 
of  lofty  cliffs.  This  platform  is  a  simple  projection  of  the 
lower  layer  of  the  cliff' ;  from  above  it,  the  waves  have 
carried  away  the  rock  to  a  distance  inward  of  fifty  to  one 
hundred  and  fifty  yards.  At  Port  Jackson,  Newcastle,  and 
WoUono-onu;  Point  are  fine  exhibitions  of  it." 


NOTE    ON    HAWAIIAN    PRONUNCIATION. 

The  follovvins;-  rules  comprise  nearly  all  that  is  essential  for  correctness 
in  the  pronunciation  of  Hawaiian  words,  except  on  one  point,  —  that 
of  accentuation  :  — 

1.  Sound  the  vowels  as  in  Italian,  and  the  consonants  (eight  in  number, 
A,  k.  I,  m,  )i,  J),  t,  w)  as  in  English,  except  ?o,  the  pronunciation  of  wliich 
is  between  that  of  w  and  v. 

2.  Make  as  many  syllables  in  a  word  as  there  are  vowels.  The  word 
Hawaii  is  not  an  exception,  although  the  distinction  of  the  closing  sylla- 
bles might  not  be  perceived  by  one  unfamiliar  with  tiie  spoken  language. 
Turn  has  two  syllables,  ICa-tc;  Kilauea  has  five,  Ki'la-ii-e'a;  but  the 
second  and  third  are  nearly  blended  in  the  pronunciation. 

3.  Never  make  a  syllable  end  with  a  consonant.  Thus,  Ilo'no-lu'lu  is 
right,  not  Hon' o-hc' lit ;  Ha'le-a'ka-la,  noi  Hal' e-ak'a-la.  In  Hawaiian  all 
words  as  well  as  syllables  end  in  a  vowel,  and  two  consonants  have  always 
a  vowel  between  them. 

4.  An  apostrophe  between  two  vowels  implies  that  a  Jc  is  dropped,  and 
that  an  interruption  of  the  voice  is  there  required  in  pronunciation,  —  as 
in  Halemauma''u. 


INDEX. 


A  A,  features  of,  9,  33. 

formation  of,  192,  206,  241. 
Abich,    M.,    eruption   of    Vesuvius    in 

1834,  267. 
Adams,    O.   B.,  Mount   Loa   crater   in 

1873,  201. 
Agassiz,    A.,    Three    Cruises    of     the 

Blake,  367. 
Alexander,  J.  M.,  map  of  Mokuaweo- 
weo,  40,  181. 

cataracts   of   lava    at    Mount    Loa 

crater,  237. 
volcanoes  over  cross-fissures,  263. 
Alexander,  W.  C.,on  Kilauea  in  1833, 

56,  57. 
Alexander,  W.     D.,    Surveyor-General, 
maps  of  the  Islands,  27,  270. 
trip  up  Haleakala,  270. 
Allen,  O.  D.,  analysis  of  scoria  crust  of 

Kilauea,  163. 
Analyses  of  rocks,  163,  342,  348. 
Andesyte,  6,  353. 
Andrews,  Dr.  L.,  Mount  Loa  crater  in 

1843,  185. 
Arctic  Sea,  depths  of,  370. 
Ascensive  force,  16,  170. 
Ashes,  volcanic,  1. 
Atlantis,  369. 
Augite,  in  lavas,  4. 

feathery,  in  Hawaiian  lavas,  E.  S. 
Dana,  319. 
Australia,  denudation  in,  385. 

Bahamas,  depths  near,  368. 
Baker,  E.  P.,  eruption  of  1868,  89. 
Kilauea  in  1889,  123. 


Baker,  E.  P.,  source  of  lavas  of  1852, 
188;    of  eruption  of  1880-1881,  205. 

Mount  Loa  crater  in  1885,  210;  in 
1888,  215. 

lava-stalactites    with     bent     ends, 
210. 

collections  of  rocks,  318,  335,  346. 
Baldai-san  eruption,  253. 
Basalt,  6. 

Basaltic  structure,  7. 
Basalt-volcano,  142. 
Basic  and  acidic  rocks,  146. 
Bathymetric  map,  358. 
Bingham,  H.,  on  Kilauea,  55. 
Bird.  Miss  Isabella  L.,  Mount  Loa  cra- 
ters in  1873,  199. 
Bird  Island,  317. 
Bishop,  A.,  38,  47. 
Bishop,  S.  E.,  survey  of  Oahu,  285. 

survey  of  Bird  Island,  317. 

rocks  of  Western  Maui,  351. 
Black  Ledge  in  Kilauea,  34,  46,  127. 
Blow-holes,  Blowing-cones,  17,  49,  58, 

71. 
Boiling  action  in  Kilauea.  68,  153,  159. 

lava-lakes  of  1840,  69. 
Bombs,  so-called,  10,  245. 
Brigham,  William  T.,  memoir  by,  40. 

Kilauea  in  1864-1865,  85;  in  18G8, 
89;  in  1880,  96. 

map  of  Kilauea,  84,  134,  138. 

on  formation  of  Pele's  hair,  160. 

Mount  Loa  in  1851,  186;  in  1864, 
193;  in  1880,  203,  204. 

on  lava-stalactites,  341. 

on  vapors,  155 


50 


394 


INDEX. 


Budd,    Thomas    A.,    Lieut.,    depth    of 

Kilauea,  67. 
Byron's  Voyage  and  Journal,  37,  50,  54. 

Carbonic  acid,  8. 

Castle,  S.  N.,  Kilauea  in  1837,  59. 

Caves  in  lava-stream  near  Hilo,  209. 

in  elevated  coral-reef,  Oahu,  303, 
Challenger   Expedition,   Mount  Loa  in 

1875,  202. 
Chamberlain,  L.,  on  Kilauea,  53. 
Chase,  Captain,  Kilauea  in  1838,  59. 
Cheever,   H.   T.,   Island    World   of   the 

Pacific,  81. 
Chrysolite  of  lavas,  6,  298,  324,  327,  343. 
Cinders,  1,  7. 
Cinder-cones,  3,  13,  279. 
Coan,  T.,  publications  of,  38.  40. 

on  Kilauea  in  1840,  til  ;  in  1844, 
1846,  74,  76;  in  1848,  80;  in 
1851,  81;  in  1853;  81;  in  1855, 
82;  iu  1856-1858,  83;  in  1862, 
84;  in  1863,  85;  in  1866,  88;  in 
1868,  89;  in  1869,  1871,  1872, 
92;  in  1874,  94;  in  1879,  95. 
Mokuaweoweo  in  1843,  185;  in 
1849,  185;  in  1851,  186 ;  in  1852, 
186:  in  1855,  189;  in  1859,  193; 
in  1865,  194;  in  1868,  194;  in 
1872-1874, 197-199;  in  1875-1877, 
202;  in  1880,  203;  in  1881,  204, 
205. 
map  of  Kilauea  in  1844,  75. 
Coan,  T.  Munson,  on  Kilauea  in  1855. 

82. 
Cohen,  analyses  by,  348. 
Columnar  basalt.  7. 
Conduit,  volcanic,  15,  151. 
Cones,  forms  of,  11,  13. 
cinder-made,  3. 
cinder,  in  Haleakala,  279 ;  of  Oahu, 

292. 
debris,  in  Halema'uma'u,  Coan,  170, 
171;  in  1887,  103,  11.3,  119,  130; 
views  of,  107,  111.  121. 
lateral,  13,  22,  245. 
tufa,     14;     of    Nanawale,    64;     of 
Oahu,  292. 
Copper   sulphate,    or   copper  vitriol,  at 
the  sulphur-banks  of  Kilauea,  73. 


Crater,  characters  and  origin  of,  1,  149, 
230. 

work  within,  16,  20,  23,  153,  222, 
265. 
Cummings,  Miss  C.  F.  Gordon,  Kilauea 
in  1879,  95. 

Dampier,  R.,  sketch  of  Kilauea  by,  38. 

52. 
Dana,   E.   S.,    petrography   of   Hawaii, 

318;  of  Maui,  349;  of  Oahu,  353. 
Darwin,   valley-making   in  New  South 

Wales,  386. 
Daubree,   A.,  entrance  of  water  to  vol- 
canic conduit,  158. 
Debris-cones,  103,  113,  119,  130,   170, 
171. 

destruction  of,  176. 
Deep-sea  troughs  and  topography,  360. 

origin  of,  363. 
Denudation  of  volcanic  islands,  373;  of 
Tahiti,  373 ;  of  Hawaiian  Islands,  380; 
of  New  South  Wales,  385. 

cause  and  methods  of,  381,  386. 
Diabase,  6. 

Diamond  Head,  282,  293. 
Dibble,  I.,  eruption  of  1789,  41. 
Dioryte,  6. 

Dissociation  iu  liquid  lava,  158. 
Dodge,  F.  S.,  paper  of,  41. 

map  of  Kilauea,  Plate  HI.,  34,  106. 
Kilauea  in  1886-1888,  106,  109. 
sections  of  Halema'uma'u  in  1888, 

120. 
size   of  Keanakakoi    and   Kilauea- 
iki,  66. 
Doleryte,  6. 
Dolphin  .shoal,  362. 
Douglas,  David,  publications  of,  38. 
on  Kilauea,  57-59. 
Mount  Loa  in  1834,  183. 
Drayton,    J.,    sketch    of    Kilauea,    32, 
136. 

plan  of  Haleakala,  274. 
Driblet-cone,  17,  71,  85,  147. 
Driblet-cones,  making  of,  160. 
Dutton,  C.  E.,   report  of,  on  Hawaiian 
volcanoes.  140 

Kilauea  in  1882,  97. 
Mount  Loa  in  1882,  210. 


INDEX. 


395 


Earth's     feature-lines,    comprehensive 

character  of,  371. 
Earthquakes,  22. 

of    Hawaii   in    1868,    89,    231;     of 

1886,  98,  99;  of  1887.211. 
agency  in  eruptions,  231. 
of    Mount     Loa,    discharging    Ki- 
lauea,  231. 
Effluent  discharges,  2,  169. 
Eld,  Henry,   Lieut.,  depth  of    Kilauea, 
67. 

on  Mount  Loa  crater,  183. 
Ellis,  William,  Journal  of ,  35. 

sketch  of  Kilauea  by,  46,  47,  50. 
Emerson,  J.  S.,  paper  of,  41. 

Kilauea  in  March,  1886,  and  map, 
100,  101,  106. 
Erosion.     See  Denudation. 
Eruptions,  submarine,  2. 
subaerial,  3. 

of  Kilauea  in   1823,  45  ;  1832,  55; 
1840,  61;  1868,  88;  1886,  98.    . 
periodicity  or  not  of,  124. 
dependence  on  rains,  125. 
of  Mount  Loa  in  1832,  180 ;  1843, 
185;  1852,  186;  1855,  189;  1859, 
191;  1868,  194;  1877,  submarine, 
202;  1880-1881,  204;  1887,  211. 
characteristics  and   causes    of,    15, 

21,  228,  230. 
explosive,  23  ;  of  Kilauea  in  1789, 
41 ;  of  Tarawera,  246 ;  of  Kraka- 
toa,  249;  of  Baldai-sau,  253. 

Fault-planes,  174. 

Felsyte,  5. 

Flames  in  Kilauea,  Brigham,  88,  96. 

observed  in  1887,  119. 
Floating  island  of  1838,  60. 
of  1882-1886,  98-100. 
disappearance  of,  176. 
Fountains   in  summit  crater  of  Mount 
Loa,    198,   199,   201,   203,   219,  223, 
225. 

of  Mount  Loa  eruptions   in   1852, 
187;  1859,191;  1868,195;  1887, 
212,  236. 
Fouque,  dissociation  of  elements,  8. 
Fuller,    Mount  Loa  eruption  of    1852, 
187. 


Fumaroles,  3. 

Fusibility  of  rocks,  7,  144. 

effect  of,  on  volcanic  action  and  on 
forms  of  cones,  12,  143. 

Gabbro,  6. 

Gases,  volcanic,  7. 

Glass,  volcanic,  4,  330. 

Glauber  salt,  8,  228. 

Goodrich,  Joseph,  letters  of,  38,  53-55. 

Granite,  5. 

Granulyte,  5. 

Gravitational   pressure,  effects  of.   179, 

235. 
Gi-een,    William    L.,  Vestiges    of    the 
Molten  Globe,  41. 

eruption  of  1859,  192. 

eruption  of  1868,  196. 

Mount  Loa  crater  in  1873,  200. 

on  source  of  Mount  Loa  fountains, 
225. 

theory  of  the  origin  of  the  earth's 
features,  263. 
Gulick,  O.  H.,  Kilauea  in  1863,  84. 
Gypsum,  8,  73. 

Hale.\kala,  features  of,  273. 
Drayton's  map  of,  273. 
action    ending    in  cinder-ejections, 

274,  279. 
last  eruption  of,  and  origin  of  crater, 

277. 
a    solid    mountain,    according     to 
Preston's  pendulum  experiments, 
279. 
Halema'uraa'u,  first  mention  of  name  by 
Count  ytrzelecki,  60. 
sections  of   1S86-1S88,  Dodge,  120. 
See,  further,  Kilauea. 
Haskell,  R.  V.,  Mount  Loa  ei'uption  of 

1859,  191. 
Hawaii,  general  features,  28. 
Hawaiian  Islands,  features  of,  25.         • 
publications  on,  35. 
origin  of,  259,  261. 
deep-sea  troughs  near,  363. 
denudation  in,  380. 
rocks  of,  E.  S.  Dana,  318. 
Hawes,  G.  W.,  analysis  by,  163. 


;96 


INDEX. 


Heat,  loss  of,  in  conduit,  16. 
Heights  of  Hawaiian  mountains,  25. 
Hematite,  7. 
Hillebrand,  William,   Kilauea  in   1868, 

89,  233. 
Hilo,  29. 
Hitchcock,  C.  H.,  projected  stones  about 

Kilauea,  43. 

Mount  Loa  crater  in  1883,  210. 

Kakuku  eruption  of  1888,  196. 

Hitchcock,  D.  W.,  Mount  Loa  in  1870, 

197  ;  in  1888,  214. 

eruption  of  1880-1881,  204. 
formation  of  aa,  206. 
Hitchcock,   E,    G.    and   H.  R.,    Mount 

Loa  crater  in  1873,201. 
Honolulu.  282. 
Hualalai,  Mount,  28. 
Hydi'ostatic   pressure,    etfects    of,    179, 

235. 

Jackson,  J.  C,  aiialy.sis  of  a  lava- 
stalactite,  342. 

Jocelyn,  S.  S.,  engraver  of  the  first 
sketch  of  Kilauea,  36. 

Johnston-Lavis,  on  bombs,  11. 

Jones,  George,  earthquakes  of  1887,  211. 

Journal  of  the  Mission  Deputation  of 
1823,  35. 

Judd,  Dr.  G.  P.,  on  Mount  Loa  crater, 
183. 

Kaliuw'aa,  on  Oahu,  287. 
Kauai,  features  of,  305. 
structure  of,  306. 
lateral  cones,  309. 
elevated  sand-hills,  316. 
Kea  Range  in   the    Hawaiian    Islands, 

127. 
Keanakakoi,  66. 

Kilauea,   view    of,    Drayton's,    32;    El- 
lis's, 46,  47,  50;  Dampier's,  52;  Chase 
♦   and  Parker's,  60;  Perry's,  87. 

Map  of.  Lieutenant  Maiden's,  51 ; 
Wilkes's,  66,  133,  135;  Lyman's, 
79:  Brigham's,  84,  134,  138; 
Lydgate's,  93,  94. 
floor  of,  and  other  interior  features, 
34. 


Kilauea,  eruption  of  1789,  41,  95,  249; 
1823,    45;     1832,   55;    1840,    61,   67; 
1868,   98;  1886,  98. 
a  basalt-volcano,  142. 
cycle  of  movement  in,  141. 
lava-column,  size  of,  151. 
ordinary  work  of,  153. 
lifting   of   floor  of,  C.  Lyman,  76. 

170. 
lifting    of   floor  of  Ilalenia'uma'u, 
Dodge,  109,  120;  source  of  ascen- 
sive  action,  175. 
contrast  with  Vesuvius,  34,  265. 
relation  to  Mount  Loa,  258. 
rocks  of,  E.  S.  Dana,  342. 
Kilauea-iki,  60. 
Kinney,  H.,  eruption    of    Mount  Loa, 

1852,  187. 
Kohala  Range,  28. 
Krakatoa,  249. 

Kiukenberg,  C.  Fr.  W.,  on  Pele's  hair, 
161. 

Labradokite,  6. 

Laccolitlis,  Laccolites,  15. 

Ladrones,  great   depth  near   Southern, 

364. 
Lapilli,  18. 

Lateral  cones,  origin  of,  245. 
Lava,  1,  4.     See,  further.  Rocks. 
Lava-streams,  9,  114. 

rate  of  flow  of,  Coan,  189. 
Leucite,  Leucite-rock,  5. 
Limonite,  7. 
Loa  Range,  27. 

Loomis,  E.,  Kilauea  in  1824,  54. 
Lydgate,  map  of  Kilauea,  93,  94. 
Lyman,     Chester,     Kilauea     in     1846, 
76. 

debris  ridge   of  Kilauea,  in   1846, 

77,  139. 
ascensive  action,  78,  170. 
map  of  Kilauea,  79. 
Lyman,  E.  E.,  conflict  of  lava-streara 

and  water-stream,  206. 
Lyman,  F.  S.,  Mount  Loa,  fountain  of, 
"l852,  188. 

Kilauea  in  1868,  89,  194. 
Lyons,  C.  J.,  Kilauea  in  1878,  94. 
Lyons,  L.,  eruption  of  1859,  101. 


INDEX. 


397 


Maby,  J.  H.,  Kilauea  in  1886,  98. 
Maiden,  Lieutenant,  map  of,  38. 
Map  of  Hawaii,  frontispiece;  of  Ha- 
waiian Islands,  26,  261;  of  Kilauea 
(see  Kilauea)  ;  of  Mokuaweoweo,  40, 
181;  of  Maui,  271;  of  Oahu,  283; 
of  Tarawera  region,  247 ;  of  Tahiti, 
37.5. 

bathymetric,  358. 
Marcasite,  8. 

Maui,  description  of,  269. 
map  of,  271. 

eccentric  form  of  craters,  281. 
rocks  of,  E.  S.  Dana,  349. 
west,  crater  of,  280. 
drift-sand  ridge,  282. 
Merritt,  VV.  C,  summit  of  Mount  Loa 

in  1888,  215. 
Metamorphic  action,  178. 
Metamorphisrn  in  connection  with  vol- 
canic  action,  exemplified  in  the  sta- 
lactites and  in  ejected  blocks,  254. 
Microlites  of  lavas,  E.  S.  Dana,  331. 
Mitchell,  Major,  valleys  of  New  South 

Wales,  386. 
Mokuaweoweo.     See  Mount  Loa. 
Mount   Loa,    map  of   cratei-,  of  J.    M. 
Alexander,  181;   of  Wilkes,   184;  de- 
scription of,  180. 

eruption   of  1832,  180;  1843,  185; 
1852,  186;  1855,  189;  18.39,  191; 
1868, 1877,  submarine,  202;  1880- 
1881,  204;  1887,  211. 
periodicity  in  eruptions,  217. 
relation  to  seasons,  219. 
ordinary  activity,    including   lava- 
fountains    hundreds    of   feet     in 
height,  221,  222. 
rate  of  flow  of  lavas,  238. 
heights   of   place   of  outbreak  and 
relations  to  diameters  of  crater, 
229,  230 
cause  of  eruptions  of,  235. 
form  of  dome  due  to  volcanic  ac- 
tivity, 2.56. 
rocks  of,  E.  S.  Dana,  319. 

Narrati\e  of  the  Mi.ssion  Deputation 

of  1823,  35. 
New  South  Wales,  denudalion.  385, 


New  Zealand,  explosive  eruption  of,  246. 

range  of  islands,  361,  371. 
Nichols,  J.  W.,  Kilauea  in  1874,  94. 
Nihoa,  island  of,  317. 
Nordhoff,  Northei-n  California,  Oregon, 
and  the  Sandwicli  Islands,  90. 

Oahu,  features  of,  282,  285. 
precipice  of,  282,  288,  290. 
tufa-cones  of,  292,  299. 
salt  lake  of,  297. 
evidence  of  change  of  level.  302. 
artesian  borings,  293. 
Obsidian,  5. 

Oceanic  depths  about  the  Hawaiian  Isl- 
ands, 363. 

topography,  Pacific,  360,  363,  366; 
Atlantic,  365,  367,  369;  Arctic, 
370. 
Olivine.     See  Chrysolite. 

Pacific  Ocean  topography,  860. 
Pahoehoe,  9,  33. 

formation  of,  192. 
Pal  agon  ite,  7,  292. 
Paris,  T.    D.,  Mount  Loa,  eruption  of 

186S,  194. 
Parker;  Captain,  Kilauea  in  1838,  59. 
Patagonian  plateau,  362. 
Pele's  hair,  first  mention  of,  Ellis,  48. 

formation  of,  in  1840,  70;  in   1880, 
160. 

description  of,  160,  161,  348. 
Pericentric  action,  1. 
Perry,  sketch  of  Kilauea,  of  1864,  87. 
Phacolite,  328. 
Pickering,  C,  eruption  of  Kilauea,  64. 

on  Halema'uma'u  in  1840,  68,  73. 
Pitchstone,  5. 
Pit-craters,  33. 

Polynesian  Researches,  Ellis.  36. 
Porphyry,  5,  6. 
Preston,  E.  D.,  pendulum    experiments 

on  Haleakala,  279. 
Prestwich,  J.,  Water  in  Volcanic  Erup- 
tions, 157. 
Projectile  action,  21  ;  cause  of,  16,  17, 
158. 

eruption  of  Kilauea,  41. 
Pumice,  5,  42. 


198 


INDEX. 


Punchbowl,  282,  292. 
Pyrite,  8. 

QuARTZ-syenyte,  5. 
Quartz-trachyte,  5. 

IvKD  iron-oxide,  7. 
lihyolyte,  5,  7. 

Richardson,  Mount  Loa  in  1865,  194. 
Rocks  of  Hawaiian  Islands,  E.  S.  Dana, 
318. 

basaltic,  319. 

specific  gravit}'  of,  320. 

feathery  forms  of  augite  in,  320. 

chrysolite  of,  324,  327,  343. 

cavities  having  minute  crystals  of 
labradorite  and  augite,  326. 

glassy  lavas,  33U. 

the  heavier  chrysolitic,  independent 
of  altitude,  347. 

degree  of  crystalline  texture  de- 
pends on  rate  of  cooling  and 
not  a  maik  of  geological  age, 
314 

of  Kilauea,  E.  S.  Dana,  342,  348, 
glass  often  absent  or  nearly  so. 
347. 

of  Mount  Loa,  819. 

of  Oahu,  259,  353. 

ejected  blocks,  about  Kilauea.  344. 

relations  of  Kilauea  rocks  and  those 
of  Mount  Loa  summit.  347. 

ScACCHi,  A.,  on  Vesuvius,  265. 
Scandinavian  plateau,  362. 
Scoria,  scoriaceous  lava,  9. 
origin  of,  162. 
thread-lace,  163. 
Shepherd,  Capt.  John,  R.  N.,  61. 
Silvestri,  on  Hawaiian  rocks,  318,  348. 
Solfntara,  3,  8,  73,  228. 
Soundings,  oceanic,  360. 
Stalactites  of  Kilauea  in  1840,  71:  in 
1864,  Brigham,  86. 

of    cave    near    Hilo,    209;    E.    S. 
Dana,  332. 
Stewart,  C.  S.,  publications  of,  37,  52, 

55. 
Strzelecki,  publications  of,  39,  60. 


Strzelecki,  valley-making  in  New  South 

Wales,  386. 
Sulphur-banks  of  Kilauea,  73. 
Sulphurous  acid,  8. 
Superfluent  discharges,  2.  169. 
Syenyte,  5. 

Tacchini,  on  Hawaiian  rocks,  318. 
Tahiti,  interior  mountains  of.  313. 

denudation  of,  373. 

ascent  of  Mount  Aorai,  377. 
Trachyte,  5,  7. 
Tufa,V. 

Tufa-cones,  14,  292,  299. 
Tufa-hills  near  Nanawale,  64. 

Valleys.     See  Denudation. 

Van  Slyke,  L.  L.,  paper  of,  on  Kilauea 

in  1886,  41,  102. 
Vapors,  of  fresh-water  origin,  155,  224, 
225. 

effects  of,  in  volcanic  action,  154. 

expansive  force  of,  161. 
Vaudi-ey,  eruption  of  1859,  191. 
Vesicles,  origin  of,  20,  161. 
Vesiculation,  mechanical  effects  of,  168. 

amount  of   moisture    required  for, 
166. 
Volcanic  aslies,  1. 

gases,  vapors,  1. 

rocks,  4;  glass,  4,  7. 

action,  2,  15. 

eruptions.     See  Eruptions. 

cones,  forms  of,  11. 

islands,  denudation  of,  373. 

mountains,  interior  of,  312. 
Volcano,  characters  of,  1. 
Volcanoes  in  lines,  27. 

not  safety-valves,  264. 

of  Hawaii  and  Vesuvius,  contrasts 
and  resemblances,  265. 
Volcanoes     and    deep-sea    topography, 
3.57. 

Walker,    W.    M.,    Lieut.,    height    of 

Tahiti  peak,  373. 
Water,   actions  of,   in  the   conduit  of  a 

volcano,  167. 

in  eruptions,  169. 


INDEX. 


399 


Water,  for  volcanic  action,  sources  of, 
19,  155. 

fresh,  source  of  high  projection  of 

liquid  lava  on  Hawaii,  223,  225. 
amount  required   for   vesiculation, 

166. 
action  of  vapor  of,  or  steam,  7,  16, 
19. 
West  India  Seas,  depths  in,  367. 

and     Mediterranean,      parallelism 
between,  362. 


Wheeler,  H.  L.,  composition  of  lavas, 

350,  354. 
White  Island,  New  Zealand,  248,  371. 
Whitney,  H.  M.,  eruption  of  1868,  89, 

195;  of  1877,  202. 
Wichmann,  on  Hawaiian  rocks,  318. 
Wilkes,  Charles,  Capt.  (later,  Admiral), 
Narrative  of,  39,  62,  66,  67. 
measurements  of  Kilauea,  67. 
on  Mount  Loa,  183. 
map  of  Tahiti,  374. 


University  Press  :  John  Wilson  &  Son,  Cambridge. 


